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Full text of "The tin deposits of the Carolinas"

m 

^2 *\ North Car*, State Libranr 

v° Raieign 



THE NORTH CAROLINA GEOLOGICAL SURVEY 

J. A. HOLMES, State Geologist 



BULLETIN NO. 19 



THE TIN DEPOSITS 



THE CAROLINAS 



BY 



JOSEPH HYDE PRATT, Ph. D., Mineralogist 



AND 



DOUGLASS B. STERRETT 




RALEIGH 

E. M. Uzzell & Co., Public Printers and Binders 

1904 



~ North Carolina State Library 

V^oO* Raleigh 

THE NORTH CAROLINA GEOLOGICAL SURVEY 



J. A. HOLMES. State Geologist 



BULLETIN NO. 19 



THE TIN DEPOSITS 



THE CAROLINAS 



BY 



JOSEPH HYDE PRATT, Ph. D., Mineralogist 



DOUGLASS B. STERRETT 




RALEIGH 

E. M. Uzzell & Co., Public Printers and Binders 

1904 



TABLE OF CONTEXTS. 



PAGE. 

Board of Managers 5 

Letter of Transmittal 6 

Introduction 

Geographical Location 10 

Geology 12 

mlneralogical and chemical character of the oee 15 

Analyses of Cassiterite 17 

Associated Minerals of Cassiterite 18 

Percentage of Cassiterite in the Veins 21 

Development Work 22 

Ross Mine 22 

Ledoux property 24 

Faires property 26 

Falls property 26 

Carpenter property 27 

Chestnut Hill Vein 28 

Ormond property 28 

Hovis property : 28 

Ramseur Mill property 29 

Jones mine 29 

Tin Localities in Other Parts of the United States 30 

Maine 30 

New Hampshire 30 

Massachusetts 30 

Virginia > 30 

Alabama 31 

South Dakota 31 

Texas 32 

California 32 

Alaska 33 

Other States • 33 

Foreign Tin Localities 34 

Malay Peninsula 34 

Banka and Billiton 36 



4 TABLK OF CONTENTS 

PAGE. 

Sumatra 36 

Bolivia 37 

England 38 

Australia 38 

New South Wales 38 

Queensland 38 

Tasmania 39 

Mexico , 39 

Other localities 39 

Origin of the Tin Ore 40 

Historical 40 

Evidence bearing on origin 44 

Method of Concentrating the Tin Ore 50 

Alluvial deposits 50 

Vein tin ore 51 

Economic Value of the Carolina Tin Deposits 52 

Extraction of Tin from its Ores 53 

Reduction of the ores 54 

Refining of the crude tin 54 

The Metal Tin 55 

Uses of Tin 56 

Value of Tin 57 

Monthly average price of tin 57 

Production of Tin f 58 

Production of tin from the Carolinas 58 

World's production of tin — table of production of tin in the world 58 

Imports of tin into the United States 

Sources of Supply of Tin 59 

Stock of tin in England, America and Holland 60 

Publications of the North Carolina Geological Survey 63 

Bulletins 63 

Economic papers 63 

Reports 64 



BOAED OF MANAGERS. 



Governor C. B. Aycock, ex officio Chairman Raleigh. 

J. Turner Morehead Leaksville. 

Charles McNamee Biltmore. 

J. A. Holmes, State Geologist Chapel Hill. 



LETTER OF TRANSMITTAL. 



Raleigh, 1ST. C, May 1, 1904. 

To His Excellency , Hon. C. B. Aycock, 

Governor of North Carolina. 

Sir: — The interest that has recently been aroused in the occurrence 
of tin ore in the Carolinas has led to an examination of the deposits 
and the preparation of the present report on the Tin Deposits of the 
Carolinas, which I have the honor to submit for publication as Bul- 
letin No. 19. In this report an attempt has been made to answer as 
fully as possible the various questions that have been raised regard- 
ing the extent and occurrence of the tin ore in the Carolinas, the 
economic value of the deposits, and the world's source of supply of 
tin. 

Yours obediently, 

J. A. Holmes, 

State Geologist. 







"l^ 




a. 




O I; 

G) Pi 



THE TIN DEPOSITS OF THE CAROLINAS. 



BY 

JOSEPH HYDE PRATT 

AND 

DOUGLASS B. STERRETT. 



INTRODUCTION, 

When one considers the amount of tin that is consumed each year 
and investigates the sources of supply of this metal, he begins to 
realize that it is an important question that has been raised as to where 
the world's supply of tin is to be obtained. During the past few years 
the yearly production has not been equal to the demand, and the 
accumulated stocks of tin that have been held in various countries 
have become very much diminished since 1896. Thus, while the de- 
mand for tin is increasing, due chiefly to the large growth of the 
canning industry and the use of tin boxes and cases in shipping sun- 
dry articles, the production has not kept pace with this demand. 
Approximately 43 per cent, of all the tin produced in the world is 
consumed in the United States, and until the past year there has been 
practically no production of this metal in this country. With the 
exception of the discovery of tin in Alaska, the ore deposits recently 
located in North and South Carolina are the only ones that have been 
discovered during recent years that have offered any chance of becom- 
ing commercial producers of this metal. 

On account of the value of the metal, tin, it is possible to work 
very low grade ores, if they are in quantity. Usually there is but 
little difficulty in cleaning and concentrating a tin ore so as to obtain 
a nearly pure product. The tin mineral that constitutes the ore is 
cassiterite, a tin oxide represented by the formula, Sn 2 , and is a 
heavy mineral, having a specific gravity of ibout 6.5 to 7. 

Considering the existing conditions in the tin industry, any dis- 
covery of tin like that of the Carolinas is of importance and demands 



10 THE TIN DEPOSITS. 

attention; and it would mean much to this country if commercial tin 
deposits could be opened up, so that we would not be entirely depend- 
ent upon foreign countries for our supply of this metal. 

The discovery of tin ore in North Carolina near Kings Mountain 
was made in 1S83, and, according to Mr. John Furman,* a mining 
man from Georgia, loose pieces of cassiterite were found lying upon 
the surface b}- a } 7 oung man named Claywell, who was attending a 
school taught by Captain W. T. R. Bell. He was attracted to the 
mineral by its peculiar appearance and unusual weight ; but was un- 
able to determine its exact mineral character. Later these specimens 
were on exhibition at Boston, and Dr. Charles W. Dabney, who was 
present, noticed them, and upon testing same they proved to be the 
mineral cassiterite. Although some prospecting was done in the 
vicinity of Kings Mountain for tin ore, it was not until 1886 that any 
systematic prospecting was carried on. Early in that year Mr. John 
H. Furman spent a number of days examining the tin belt and found 
a number of samples of the tin ore, which were assayed at Ledoux & 
Co.'s laboratory in New York, and this firm later in the year retained 
Mr. Furman to make a thorough, systematic search of this region. 
In 1888 a 10-stamp mill was erected by Mr. Ledoux and his associates 
in which to thoroughly test the tin ore which was being developed; 
but, owing to litigation, work on the property ceased in the latter 
part of 1889. About the year 1892 work was begun on the Chestnut 
Hill property, but continued for only a, portion of the year. Since 
then little or no work was done on the tin belt until 1903, when 
the Ross mine at Gaffney, South Carolina, was discovered. This has 
led In renewed interest in the Carolina tin belt, and considerable 
prospecting and development work is now being done at a number 
of places along the licit. 

GEOGRAPHICAL LOCATION. 

W'lial may lie called the Carolina tin hell extends from Gaffney, 
Cherokee County, South Carolina, in a general northeasterly direction 
across this county; the southeastern corner of Cleveland County, 
North Carolina, and across Gaston and Lincoln counties, North 
Carolina. The tin deposits . found in Rockbridge County, Virginia, 
may be a continuation of the Carolina I in bell across ( Jatawba, Iredell, 

•Trans. N. Y. Acad. Sri.. Vol. VIII. Jxxh 1889, p. 142. 




36 



GRANITE 
7//////J//A METAMORPH /CROCKS 



***/. 



GNEISS- 
TIN DEPOSITS 



35 



Scale 
25 Miles -I Inch. 



J° 



34 



81° 



80 



i io, i Geolooh ai. Sketch Map Showing the Location <>k the Carolina Tin Deposits. 



THE TIN DEPOSITS. 11 

Yadkin and Sairry Counties, North Carolina. The general direction 
of the rocks carrying the tin ore is the same as those in Virginia, and 
the continuation of this direction from the Carolina deposits would 
approximately cross those places in Rockbridge County, Virginia, 
where tin ore has been found. The same rocks that a.re outcropping 
in Surry County, North Carolina, are also in this same line and have 
the same general direction. The principal locality in South Carolina 
where tin ore has been found is about one mile north of Gaffney 
on land belonging to Captain S. S. Ross. For a distance of 13' 
miles from a point about a mile northeast of the Ross mine no tin 
minerals have as yet been found. The next place in the belt where 
tin is known to occur is a short distance northeast of Grover, North 
Carolina, a station on the Southern Railroad. From this point tin ore 
has been found almost continuously for over 14 miles to within 
a few miles of Lincolnton, Lincoln County, North Carolina, and it 
is reported to have been found a few miles northeast of Lincolnton, 
but no authenticated record of this discovery could be obtained. No 
tin has thus far been found in North Carolina northeast of the Lin- 
colnton locality, nor in Virginia until the Rockbridge County deposits 
are reached. 

A general idea of the location of the Carolina tin deposits is given 
in the map, Figure 1. The principal deposits that have thus far been 
located are the Ross mine at Gaffney, South Carolina ; the deposits in 
the vicinity of the town of Kings Mountain, North Carolina ; on the 
southern end of Chestnut Ridge, about 2% miles northeast of Kings 
Mountain ; and on the John E. Jones plantation, 7 miles northeast 
of Kings Mountain. 

The Southern Railroad passes over a considerable portion of the tin 
belt, following almost the general direction of the formation from 
Kings Mountain to Gaffney. At the former place the railroad turns 
sharphy to the east, crossing the tin belt, which continues toward the 
northeast. Thus, any commercial deposits that may be developed will 
have good railroad facilities, not being more than a few miles from the 
railroad. Those on Chestnut Ridge are not over two miles from the 
railroad, and the ore mined could easily be hauled to the railroad at 
small expense. If the Jones deposit proves to contain tin in any large 
quantity, it would still be profitable to haul the ore to the railroad at 



12 THE TIN DEPOSITS. 

Bessemer City, a distance of about 4 miles, if it did not prove 
feasible to build the railroad to the deposits. 

GEOLOGY. 

The section of North Carolina and South Carolina in which the tin 
belt occurs is close to the border of the large area of Archean gneisses 
which extend over a large portion of the western part of North Caro- 
lina and the northwestern portion of South Carolina. Bordering these 
gneisses on the east, there is a series of granites and other igneous 
rocks extending from Cherokee County, South Carolina, across Meck- 
lenburg, Cabarrus, Rowan, Davidson, Guilford, Caswell and Person 
Counties, North Carolina, which have a general north to northeast 
direction. At the extreme southern portion of North Carolina, and 
extending into South Carolina, there is between these granites and 
gneisses a band of metamorphic rocks consisting of slates, schists, lime- 
stones, quartzites and conglomerates whose age is unknown. These 
occur quite extensively developed in Cherokee County, South Caro- 
lina, and in Gaston, Lincoln and Catawba Counties, North Carolina, 
and extend for a very short distance into Iredell County, North 
Carolina. No more of these rocks are observed in this northeast 
direction until they again outcrop in the northeastern portion of 
Yadkin County, extending nearly across Stokes County and almost to 
the Virginia line. They are in every way identical with those found 
further south and represent the same geological formation. Pene- 
trating up into these rocks in Gaston and Lincoln Counties, North 
Carolina, there is a mass of granite which is from five to ten miles 
wide. The schists vary considerably in character, sometimes being 
very siliceous and having a gneissoid structure. The general strike 
of these metamorphic rocks is northeast; and it is in this belt of rocks 
in North Carolina that the tin ore is found. The general strike of the 
pegmatitie dikes and veins carrying the tin is approximately the same 
as that of 1 1 j r ■ metamorphic rocks, N. 25° E., but near the South 
Carolina line there is a rather sharp bend to the westward, so that 
from there to Gaffney, South Carolina, the direction of the tin licit is 
aboul .\. 55° E., and il Leaves the schists to the east and passes through 
i In- Archean gneisses. The rocks in the vicinity of Gaffney, South 

Carolina, are almost entirely gneisses, similar to those I' I in North 

Carolina to the west of the metamorphic recks and which have been 



THE TIN DEPOSITS. 13 

referred to as the Archean. There are, then, rocks of two distinct geo- 
logical periods in which the tin veins have been found : (1) Those as- 
sociated with the Archean gneisses, which are found in the vicinity of 
Gaffney, South Carolina ; and (2) those associated with the schists, 
which are of a later period, and with which most of the North Caro- 
lina tin is found. The ore at the Jones mine, 7 miles northeast of 
Kings Mountain, is in greisen veins that occur in a gneissic rock, 
which may be a portion of the Archean gneisses to the west. 

As has been stated above, the main country rocks are for the most 
part crystalline schists and gneisses, the former being micaceous, 
chloritic and argillaceous, and the latter micaceous and hornblendic. 
The strike of the schistosity of these rocks is usually in a general 
northeast direction and they dip for the most part at very steep angles 
to the westward. The veins in the gneisses are dipping toward the 
east at very steep angles. 

The Kings Mountain region of North Carolina is geologically 
situated in a band of metamorphio rocks composed of slates, schists, 
limestones, qnartzites and conglomerates whose age up to the present 
time has not been definitely determined. The width of this belt near 
Kings Mountain is about 10 miles and extends in a direction about 
N. 10° to 20° E, Just east of Lincolnton, Lincoln County, it joins 
another band of similar rock, the two being separated east of Kings 
Mountain by a mass of granite. To the west of these metamorphic 
rocks are the Archean gneisses, with which the tin veins of Gaffney, 
South Carolina, are associated. The strata of these metamorphic rocks 
are tilted at very high angles to nearly vertical, and in the resultant 
alteration and erosion to which they have been subjected, the quart- 
zites have resisted these influences the most, so that they now form 
the top of the peaks and ridges such as Kings, Crowders and Ander- 
son mountains, which rise 500 to 1,000 feet above the average eleva- 
tion. It is imdoubtedly the mass of granite which is to the east 
that has tilted these metamorphic rocks and thrown them into their 
present position. 

There are a number of amphibolite dikes that have been observed 
cutting these metamorphic rocks, but they have made very little 
change in the position of the schists through which they penetrated 
beyond a metamorphic action. These sedimentary rocks were tilted 



14 THE TIN DEPOSITS. 

into their present position before the intrusion of these dikes, which 
are following partly the lamination of the schists and their general 
trend ; but in a few instances are cutting across the schist. In two or 
three instances where these dikes are cutting across the schists, there 
are approximately parallel to them veins of tin ore. Pegmatitic dikes 
are also common throughout this belt of metamorphic rocks in North 
Carolina and in the gneisses further to the west in Soiith Carolina. 
They could be followed almost continuously from three miles above 
Grover, North Carolina, to the Jones mine, 7 miles northeast of 
Kings Mountain. In one place, a short distance below Kings 
Mountain, North Carolina, the pegmatitic dike was all of 200 feet 
wide. They follow in many cases the planes of lamination of the 
schist which represent lines of least resistance. Where the pegmatitic 
dikes are cutting across the schists, they may be following old fractures 
that were produced at the time of the intrusion of the amphibolite 
dikes. 

About one-half mile below Kings Mountain the pegmatitic rocks 
begin to outcrop very boldly and continue in this way nearly to Gro- 
ver, North Carolina, a distance of 7 miles. This mass of pegmatite 
varies a good deal in width in this distance, from twenty-five to six 
hundred feet. Just in the northern edge of the town of Kings Moun- 
tain there is another strong outcrop of the pegmatite, but from this 
point there is but little seen of the pegmatite northeast until Kam- 
seur's mill is reached. Here the pegmatite has a width of about 200 
feet. 

A cross-section of the tin belt in the vicinity of Kings Mountain 
would show the following sequence: hornblende-gneiss on the western 
boundary, followed on the east by schists which are in many places 
very badly decomposed ; then a narrow bed. of limestone which is more 
or less siliceous; then quartzite; another bed of limestone; quartzite; 
schist ; to the granite on the extreme eastern portion of the belt, having 
a total width of about 10 miles. 

The term greisen is given to a granitoid rod?: composed essentially 
of quartz and tnuscovite or some related mica rich in fluorine, and it is 
associated with this type of rock that the cassiterite, when occurring 
as an ore of I in, is nearly always found. 

The tin ore of the Carolina belt occurs in greisen veins that are 
for the mosl pari in the main mass of mica schist adjoining the gneiss 



THE TIN DEPOSITS. 15 

on the west, and which extends in almost a continuous belt from the 
South Carolina line to a few miles northeast of Lincolnton, North 
Carolina. The width of this schist formation is approximately one 
mile and is bordered on the east by the limestone. At the Jones mine, 
7 miles northeast of Kings Mountain, the rocks are gneissic in 
structure. In South Carolina, where the belt has made a bend toward 
the west, the tin ore occurs in the greisen veins that are in gneiss. 

Where the tin occurs in the large pegmatitic dikes, it seems to be 
in greisen veins on the boundaries of these where the fumarole action 
would be the greatest, and probably within the larger masses of 
pegmatite, where greisen veins may have formed in shrinkage cracks, 
developed during the cooling of the magma. It has been observed, 
however, for the most part, in lens-shaped masses of greisen, such as 
are commonly found in laminated metamorphic rocks, especially 
schists, when pegmatitic dikes are intruded into them- and which are 
often called "augen." In these lenses in the schist that carry tin there 
was usually no feldspar present, but similar lenses were observed in 
the schist that did contain considerable feldspar. These, however, 
contained little or no tin. 

In the vicinity of Gaffney, South Carolina, the greisen veins carry- 
ing tin, which are in gneiss, all contained more or less feldspar which 
was nearly or completely altered to kaolin. 

MINERALOGICAL AND CHEMICAL CHARACTER OF THE ORE. 

Cassiterite, the tin-bearing mineral of the veins, is an oxide of this 
metal whose formula is Sin 2 and contains theoretically 78.6 per cent, 
of metallic tin. When chemically pure this mineral is nearly white 
in color, but it usually contains more or less ferric oxide, and its 
color varies from reddish to brown or black, varying with the per- 
centage of iron. Arsenic is also occasionally found in this mineral, 
and an arsenical cassiterite is usually yellowish in color. 

The mineral is tetragonal in its crystallization, and while in cer- 
tain localities it is sometimes crystallized, it more often is granular 
and in rough masses, especially where it is found in commercial quan- 
tity. The crystals are usually prismatic and are often twinned both 
as contact and penetration twins. It is a brittle mineral, having an 
imperfect cleavage, and breaking usually with a subconchoidal frac- 
ture. 



16 



THE TIN DEPOSITS. 



Its hardness is from 6 to 7 and its specific gravity varies from 6.16 
to 7.1, according to the amount of impurity in the mineral. When 
the percentage of iron is low the crystals are nearly transparent, but 
become nearly opaque with the increasing percentage of iron oxide. 
Its lustre is adamantine but the crystals are usually splendant. 

There are three varieties of cassiterite that are recognized as 
follows : 

1. Ordinary or tin-stone, which is the crystalline and massive 
variety obtained directly from the vein or from the broken-down 
material just below the vein. 

2. Wood-tin, which is in botryoidal and reniform shapes with a 
concentric structure which internally is fibrous but very compact. Its 
color is brownish, but of mixed shades, giving it the appearance and 
color of dried wood. 

3. Stream-tin is the mineral in the form, of sand, as it is found 
concentrated along the beds of streams and in the gravels below the 
veins. 

None of the wood-tin has been found in the Carolina belt, but the 
ordinary or tin-stone and stream-tin occur abundantly. Crystallized 
cassiterite, while not common, has been found, the better crystals 
having been obtained thus far from the Jones mine, in North Caro- 
lina. The only face that has been observed on any of these crystals is 
the pyramidal face, s (111). The crystals occur both simple, and 
twinned with e (101), as the twinning plane, and are represented by 
Figs. 2 and 3. The crystals are small, from a quarter to half an inch 





FlO. 2.— Crystal ov CASSITERITE. Fio. 3.— Twinned Crystal op Cassiterite. 

in length, and are usually of a black color. They are fairly well 
developed, willi most of the edges sharp and distinct. Some, however, 



THE TIN DEPOSITS. 



17 



are considerably elongated, as represented in Fig. 4. All the faces are 
more or less corroded and striated. Rough, partially crystallized 
cassiterite is found at many places throughout the belt, and from the 
Faires property, just south of Kings Mountain, one rough crystallized 
fragment was found which weighed nearly one-half pound. Small 
but well-developed pyramidal crystals have been found in the sands 




Fig 4.— Elongated Twinned Crystal of Cassiterite. 

taken from alongside of the road on the M. V. Hovis land. Some of 
the crystals are simply pyramids and extremely regular in their de- 
velopment, while others are elongated and twinned. The color of 
the cassiterite found in the Carolina belt varies from black to almost 
colorless, the common color being a dark brownish-black, and more 
rarely a light grayish. 

Partial analyses have been made of two varieties of the cassiterite 
found in and about the town of Kings Mountain, North Carolina, 
one a light grayish and the other a dark brown. The results of these 
analyses by Professor C. W. Dabney* are given in the table below : 

PARTIAL ANALYSIS OF CASSITERITE. 





Light 
Grayish. 


Dark 
Brown. 


Stannic oxide-- 


94.70 

.92 

Trace 

Trace 


82.99 
1. 14 
0.46 


Tungstic oxide 


Sulphur 


Arsenic 







•Bull. 74, U. S. Geol. Survey, p. 35. 



fiorih Q 



^,~\e 



Librae^ 



Raieigf 



18 THE TIN DEPOSITS. 

As is seen from the above, the percentage of stannic oxide in the 
light grayish variety is much higher than that in the dark brown, 
and this is due probably to the larger per cent, of iron that was in 
the latter sample. These percentages of stannic oxide would corre- 
spond to 74.41 per cent, of metallic tin in the light gray sample and 
65.21 per cent, in the dark brown. A sample of the pure cassiterite 
from the Jones mine has been analyzed and gave 89 ; 95 per cent, of 
stannic oxide which corresponds to 70.70 per cent, of metallic tin. 

There is a noticeable difference in the occurrence of the cassiterite 
in the veins of the southern portion of the belt from those towards 
the north. At the Ross mine, near Gaffney, South Carolina, the cassit- 
erite is associated with more or less feldspar, which has been partially 
kaolinized and in some oases completely altered to kaolin, with mus- 
covite mica and but little quartz ; and so at the present stage of the de- 
velopment work but little solid ore is obtained, the cassiterite being 
readily separated from the vein material or gangue minerals without 
the need of any crushing. As the belt is followed north, however, 
quartz becomes more abundant and the veins are composed principally 
of quartz with mica and cassiterite, thus making a firm, compact ore. 
This latter occurrence would make a true, typical greisen. In this sec- 
tion of the belt it is common to find scattered over the surface boulders 
from a few pounds to one hundred and fifty or more pounds in weight 
composed of quartz, mica and cassiterite. The tin, as a rule, is im- 
bedded more in the mica than in the quartz, and the mica in the greisen 
veins containing tin has a pale, apple-green color, and is fluoric. There 
is a small amount of partially altered feldspar occasionally found asso- 
ciated with these veins in the schist. This variation in the occurrence 
of the tin is due to the country rocks in which the veins occur, those 
to the north being for the most part in the mica and quartz schists, 
while those al; the Ross mine are cutting a hornblende-gneiss. This 
variation is discussed further under Origin of the Tin Ore. 

ASSOCIATED MINERALS OF THE CASSITERITE. 

A small amount of jet-black tourmaline in rough prismatic crys- 
inls and minute needles has been found directly associated with tin, 
both in Iff quartz and in the feldspar veins; but it is rare to thus find 
it in the veins wilh the tin. It is, however, very commonly found 



THE TIN DEPOSITS. 19 

just to one side of the vein in the schist or gneiss and in some 
instances represents a tourmalinization of the wall rock. A little 
magnetite is also occasionally found. Thus far no nuorite or any of 
the tungsten minerals have been identified in these veins, although a 
fraction of a per cent, of tungstic oxide was obtained in the analysis 
of the cassiterite. 

Pyrite, an iron sulphide, is found to some extent in the schists, but 
thus far it has been observed only very sparingly directly associated 
with the tin in the greisen veins. Chalcopyrite, a copper iron sul- 
phide, has been reported by Mr. John H. Furham,* as occurring in 
some of the deeper workings made for the tin ; and Dr. A. R. Ledouxf 
reports arsenopyrite (mispickel) as an associate of the tin. 

In the concentrates of cassiterite obtained from the washing of 
the soil and gravel at various places along this belt, there is more 
variety in the associated minerals found with the tin. The associated 
minerals of the stream-tin are magnetite, ilmenite (or menaccanite), 
garnet, monazite, tourmaline, quartz, a little pyrite, and very spar- 
ingly chalcopyrite. Of the above the monazite and garnet are con- 
fined principally to the concentrates obtained from the breaking down 
of the tin veins occurring in gneiss. The monazite was observed in 
considerable quantity in the fine concentrates from the stream-tin ob- 
tained from the gravels in the vicinity of the Ross mine. It is in 
these same gneisses, in Cleveland, Burke, Lincoln, Rutherford and 
McDowell Counties, North Carolina, that the monazite which is 
mined commercially, originated. Occasionally there is a considerable 
percentage of monazite found in the concentrates with the tin, and 
one lot of concentrates obtained from, the Ross mine that was tested 
contained 55 per cent, of cassiterite and 20 per cent, of monazite 
besides considerable garnet. 

Regarding the ilmenite, which is found so abundantly associated 
with the tin in the gravels, it is to be noted that little or none of this 
mineral has been observed associated with the tin in the veins. There 
are, however, pegmatitic veins which carry a considerable amount of 
ilmenite, but such veins carry little or no cassiterite. 

There are a number of the associated minerals of the cassiterite, as 
tourmaline, ilmenite (or menaccanite) and magnetite that are being 



Trans. N. Y. Acad. Sci.. Vol. VIII, 1888-1889, p. 144. 
tEng. and Min. Jour., Vol. XLVIII, 1889, p. 521. 



20 THE TIN DEPOSITS. 

mistaken for the tin mineral. Tourmaline can generally be distin- 
guished readily from the tin by its low specific gravity of 2.98 to 3.20, 
while that of the tin is about 7. It is not so easy to recognize the 
tourmaline by this property when it occurs in the quartz gangue, but 
it can often be at once identified by its triangular cross-section. The 
magnetite and ilmenite are much closer in specific gravity to the 
cassiterite, the former having a specific gravity of 5.1G and the latter 
of 4.5 to 5. The magnetite can readily be determined by its magnetic 
properties, but the fragments of ilmenite often closely imitate cassit- 
erite and it is occasionally necessary to test the mineral to definitely 
determine which it is. If, however, it can be compared directly with 
known pieces of cassiterite, there will be little difficulty in distinguish- 
ing the lighter weight of the ilmenite. 

The cassiterite can readily be determined by means of the blow-pipe 
test, by taking a very small amount of the very finely powdered 
mineral, mixing it thoroughly with six or eight times its volume of 
sodium carbonate, and a small amount of powdered charcoal, and then 
fusing this mixture on charcoal before the blow-pipe, when it is readily 
reduced, giving a button of metallic tin. 

The position of the cassiterite in the vein varies considerably. In 
some instances, as in a 2%-foot dike at the Jones mine, the tin 
is rather evenly distributed throughout that portion of the vein 
in which it occurs; while in others, as at the Ross mine, the tin 
is concentrated in seams which are for the most part close to the hang- 
ing wall, which is toward the east. It is also to be noted that most 
of the tourmalinization that was observed was to the east of the tin- 
bearing veins. There is also a great variation in the percentage of 
the tin mineral in the vein, there being some portions that are ab- 
solutely barren, while other portions carry a high percentage ofcassit- 
erite, and still others were containing only a moderate amount. This 
makes ii very hard to determine the actual percentage of tin in the 
vein withoul making a la rue mill test. 

Many of these lenses of grciscn, as they were followed downward, 
pinched out or narrowed to a thin seam, Iml. usually before one gave 
out another was encountered. 



THE TIN DEPOSITS. 21 

PERCENTAGE OF CASSITERITE IN THE VEINS. 

In order to obtain some idea of the percentage of cassiterite that 
the veins contained, a sample was taken from the 21/o-foot vein at the 
Jones mine, and this gave on crushing and panning a concentrate of 
practically pure cassiterite which represented 5 to 6 per cent, of the 
vein. This would be equal to about 3!/2 per cent, metallic tin. Such 
an ore carrying this percentage of tin would, if in quantity, make a 
very profitable proposition. Favorably located deposits have been 
worked that did not carry over one per cent, of this metal. 

While the above results may be accurate for the particular part of 
the vein from which the sample is taken, it does not really represent 
the average of the tin ore at the Jones mine, and this can probably 
be determined only by a mill test of a quantity of the ore. It will be 
found that even those that are very familiar with sampling would 
be unable to select from a pile of ore two samples which would agree 
with each other in respect to the amount of tin that they contain, and 
this is also true in sampling veins where only small quantities 
are taken. Dr. Ledoux, in connection with his work on the tin de- 
posits in 188S, shipped to England two car-loads of ore from the 
Kings Mountain locality which were selected by a Cornishman, who 
endeavored as nearly as possible to obtain an average of hand-dressed 
ore. The returns received from these car-load lots of ore showed one 
to contain 2.5 per cent, and the other 1.5 per cent, of metallic tin. 
From his tests on the vein ore, he was of the opinion that large quanti- 
ties of hand-assorted ore averaging one per cent, of metallic tin could 
be obtained and relied upon. The gravels in this same vicinity were 
also extensively tested, and, as stated by Dr. Ledoux, they operated 
on the bottoms and on the hill-sides along the creek and in the 
branches flowing into the creek. The richest deposits were found on 
these brandies, but their superficial area was small. The results of 
this test showed these gravels to contain from 1.5 to 2.1 pounds of 
metallic tin -per cubic yard. These concentrates, however, were 
largely contaminated with garnets and iron minerals, so that sand, 
washed clean, as much as possible without using a magnetic separator, 
varied considerably in the amount of metallic tin which they con- 
tained, their tin contents varying from 11.22 per cent, to 61 per 
cent. The gravels in this vicinity are not nearly as rich as those 



22 THE TIN DEPOSITS. 

near Gaffney, South Carolina, where the tin in the alluvial deposits 
is the result of breaking down of feldspathic veins in which the 
feldspar has been entirely decomposed and has readily freed the 
tin ore; while in the more northern portions of the belt, where the 
tin is more closely associated with the quartz and mica, in the break- 
ing down of the veins it has been left more as boulders and fragments 
rather than as loose pieces of cassiterite in the soils and gravels. 

The alluvial deposits of the Ross Mine, Gaffney, South Carolina, 
have been estimated, from the various tests that have been made, to 
average in the neighborhood of 25 pounds per cubic yard. 

It is to be noted, however, that with the exception of the Cornish 
tin mines, nearly all the world's production of tin is obtained from 
alluvial deposits and not from vein formations. The foreign gravel 
deposits are usually much more extensive than those in the Carolinas 
and are more remote from the original veins. These are described 
on pages 36 to 40. 

DEVELOPMENT WORK. 

Ross Mine. — The principal development work that has been done on 
the tin belt is at the Ross mine, one mile nearly east of Gaffney, 
South Carolina. The tin ore was first observed in 1902 as smal] 
broken crystals in the soil, which were exposed by the uprooting of 
a large tree. As soon as the specimens were identified as cassiterite, 
the soil was tested by panning and found to contain a considerable 
quantity of this mineral. It was found on the slope of a hill which 
rises about 60 feet above the level of the stream, and all over this 
slope of the hill the tin was found in the soil and gravels. Near the 
top <if the hill a shaft and an open pit were sunk, which cut into the 
saprolitic rock, in which were found saprolitic-pegmatitic dikes, carry- 
ing more or less tin ore. This pit was about 20 feet below the sur- 
face, 20 feet long, with a number of drifts running from it fol- 
lowing on different seams containing tin. The shaft extended 9 
feel below the bottom of (lie pit. Wherever the tin was found in 
place if wns associated for the most purl with feldspar, which was 
largely kaolinized, thus permitting the concentration of nil the tin 
'iic by hydraulic processes to a depth of at least ■)() feet and prob- 
ably considerably deeper. 

The I in occurs in streaks, or seams, in the saprolitic pegmatite, 
which is dipping about 50° toward the east and (dose to the hanging 



THE TIN DEPOSITS. 23 

wall. The tin was found to continue to the lowest depth worked. In 
these workings there were a nnmher of narrow pegmatitic dikes or 
lenses, all of which carried tin. 

As these pegmatitic dikes were followed toward the southwest by 
the drifts they were found to be cut off in a distance of about 20 to 30 
feet by a slickenside face which undoubtedly represents a line of 
faulting. The extent of the displacement was not determined. 

Just above this shaft and pit and about 400 feet from the stream, 
a shaft 40 feet in depth was sunk and trenches were cut across the 
supposed strike of the veins, but there was only a small amount of 
tin obtained, although one fragment was found weighing about 3 
pounds that was nearly pure cassiterite. None of the pegmatitic dikes 
were encountered in this work. This result was to be expected and 
is due to the faulting. 

Numerous pits and trenches have been made from here to the 
stream and all showed the presence of tin ore, some carrying only 
about 12 pounds to the cubic yard, and some carrying as high as 
75 pounds. The average for all this soil and gravel will be about 
25 pounds per cubic yard. 

At the stream a trench was run back into the hill for about 40 
feet, following on bed rock. About the bed rock there was a stratum 
of gravel 1 to 3 feet in thickness overlain with soil which was 2 feet 
thick at the lower end of the trench and 6 to 8 feet at the upper end. 
Both the gravel and soil carried a good quantity of tin ore. 

The area over which the cassiterite has been found in the soil and 
gravels is about 1,000 by 600 feet, and all of this material will un- 
doubtedly pay to wash for this mineral. This alluvium varies in 
depth from a few feet to 8 or 10 feet, and it should all be treated 
hydraulically. There is a sufficient water supply close by for this 
purpose. 

In tracing the float-tin from the Ross mine it was found almost 
continuously for half a mile southwest and for one and one-half miles 
in a direction about 1ST. 55° E. ; but no deposit of any importance has 
thus far been located. From this point no more tin has been found 
until a point was reached about 3 miles above Grover, North Caro- 
lina, a total distance of about 13 miles, in which there is no au- 
thentic record of any tin ore having been found. Pegmatitic dikes 



24 THE TIN DEPOSITS. 

have, however, been observed quite extensively developed in this in- 
tervening area and they are especially prominent just above Grover, 
!STorth Carolina. It is probable that more systematic prospecting will 
reveal deposits of cassiterite in this portion of the belt. From this 
point tin ore has been found almost continuously to a mile or so 
above Lincolnton, a total distance of about 28 miles, although the 
principal deposits are at a distance of 7 miles northeast and south- 
west of Kings Mountain. It is near Grover, North Carolina, that 
the general direction of the belt changes from N". 25° E. to 1ST. 55° E. 

The next point at which any work has been done for tin is about 
3Yo to 4 miles southeast of Kings Mountain, where a cut has been 
made about 6 feet deep on the edge of a mass of pegmatite. These 
rocks carried cassiterite in small particles, and could be traced by 
means of surface pieces for a distance of about 100 yards. At an- 
other point, about one-half mile to the north, good ore was found as 
float just below a large mass of amphibolite rock. A trench had 
been dug below this amphibolite, which penetrated through mica 
schist and encountered a tin-bearing greisen. 

In prospecting for tin in North Carolina where the pegmatitic 
dikes are not decomposed to any considerable extent, it has been the 
custom to sink a shaft in the schist "jtist to one side of the pegmatite 
and then cross-cut the pegmatite from the bottom of the shaft. In 
many instances the schist is more or less decomposed and is very 
readily worked without any blasting. 

Ledoux Property. — Two and a half miles northeast from this point 
is the Ledoux* tin property, which was worked quite extensively some 
years ago. A number of prospect trenches and shafts showing the 
existence of tin ore were made on the contact of the pegmatite and 
sclii^l and others entirely within the pegmatite. There were three 
cross-cut trenches made which pass through the pegmatite to schist 
on I he easl and two other trenches that followed along the contact. 
From one nf these latter a shaft was sunk, which is now partially 
filled ii|>. 'Flic strike of these masses of pegmatite was 1ST. 25° E., 
and then followed to a certain extent the lamination of the schists. 
Their dip, however, was nearly vertical. Jusl west of the old mill- 
site m shaft was sunk which opened up a body of good ore. In digging 

"Kmr. ;m.| Min. Jour., Vol. 48, 1880. p. 521. 



THE TIN DEPOSITS. 25 

the foundation for the mill it was reported that good ore was un- 
covered. A short distance to the south of the mill there has also been 
considerable prospecting done by means of trenches and shafts, which 
were generally made where float-tin was found in boulders. In the 
bottom of one of these shafts chalcopyrite is reported to have been 
encountered after working through a number of feet of the tin ore." 
Arsenopyrite (mispickel) has also been found associated with the 
tin in the Ledoux property. This is somewhat similar to the Corn- 
wall deposits, where their work first penetrated through a body of tin 
ore, then into copper ore and again into tin ore. One thing to be 
noticed in connection with the deposits at this point is that the vein, 
which is nearly perpendicular, or dipping a few degrees to the east, 
is cutting across the lamination of the schist which is dipping toward 
the west. 

About half a mile below the mill a great deal of float-tin has been 
found in boulders on the summit of a small hill, and the greater part 
of this was hauled to the mill for treatment. The greisen outcrops 
on top of this hill and small particles of tin ore were observed in 
some of the boulders and fragments broken off. A large trench had 
been cut in the pegmatite, but it apparently failed to reveal the 
source of the rich boulders of greisen. 

In a recent communication, Dr. Ledoux* says regarding the work 
that was done in 1888 and 1889 under his direction on these tin 
deposits, that the rock was tested from various openings where they 
gave indication of containing tin, and that without any sorting they 
yielded from. 0.3 per cent, to 0.6 per cent, of metallic tin. With 
ordinary negro laborers who were simply instructed to throw in one 
pile all pieces which appeared to contain tin, and reject the others, 
they sorted the ore up to a grade which yielded from 0.75 per cent, 
to 1.10 per cent, of metallic tin. It was found impossible to sample 
the deposits by hand or even to determine the average percentage of 
tin on the dumps where the work was being carried on, and for that 
reason a working plant consisting of a 10-stamp mill with vanners, 
double-decked huddle, and burlap sluices was erected. A number of 
holes were put down with the diamond drill, principally for deter- 
mining the character of the strata and whether the greisen extended to 
any considerable depth, which was found to be the case. 



"Letter to Joseph Hyde Pratt, dated New York, May 6, 1904. 



26 THE TIN DEPOSITS. 

Adjoining the Ledoux property on the north is what is known as 
the limestone tract, deriving its name from the fact that there is con- 
siderahle limestone on the property. There has been a small amount 
of float-tin picked up as fragments and in small greisen boulders. ~Ro 
ore has been found thus far in the limestone. 

Faires Property. — On the Ei. C, Faires plantation, which is near 
the southwestern boundary of the town of Kings Mountain, con- 
siderable tin ore was found at a number of places 100 yards or so 
apart, which are about one-fourth of a. mile southeast of where the 
town boundary line crosses the track of the Southern Railroad. There 
are a number of large masses of pegmatite outcropping here on the 
surface. About a quarter of a mile to the southwest, where this 
property joins the Weir plantation, a little tin ore has been picked 
up in some of the gulleys. As the pegmatitic dikes were followed in 
this direction they became wider, increasing from 40' feet on the 
Faires property to about 200 feet on the Weir property. If there 
is any tin associated with these large masses of pegmatite, it is 
probably in small quantity, as a casual prospecting failed to reveal 
any. 

Falls Properly. — To the northeast of the Faires plantation a small 
amount of work has been done on the Mrs. Lizzie Falls place on the 
opposite side of the branch from where the tin ore Avas found on the 
Faires place. A number of shafts were sunk and ditches cut ; but 
few of them showed any tin ore. Considerable rich ore was encoun- 
tered in one of these shafts, about 4 feet from the surface ; but it 
gave out in a few feet, due to the pinching out of the vein. The seams 
of greisen were from 2 to 8 feet in width, following the lamina- 
tion of the schists. The other shaft that was sunk, while it did not 
bow as rich bunches of ore as the first one, was in ore al the bottom. 
Fig. 5 is a map of the country in the immediate vicinity of Kings 
Mountain. 



THE TIN DEPOSITS. 



27 



Ttleqrabh. 
/ Line 




GNEISS 
SCHIST 
LIMESTONE 
PEGMATITE 

TIN ORE 



TIN ORE IN 
VEINS 
««*. POLE NUMBER 
ROADS 

Scale 



J Inch - 300 yds. 
as. r r r t t 



Fig. 5.— Map of the Kings Mountain Tin Region. 

The next place where cassiterite has been found in any quantity is 
in the northern part of the town, about 100 yards south of where 
the road crosses the railroad track. A number of small masses of 
greisen were observed containing more or less cassiterite. The 
mineral is in small pieces from the size of a grain of sand to that of 
a pea. This greisen can be traced across the Kudisill lot and is ob- 
served in the street beyond. 

Fifty yards to the west of the railroad-crossing a small amount of 
float-tin has been picked up and near by small boulders of greisen 
have been observed. For a distance of 50 yards to the west tin 
ore can be picked up here and there over a considerable part of the 
surface. 

Carpenter Property. — Following towards the northeast to the south- 
ern end of Chestnut Ridge, about 2 to 2% miles northeast of 
Kings Mountain, on the property of Mr. M. M. Carpenter, of 



28 THE TIN DEPOSITS. 

Kings Mountain, a large number of boulders of greisen have been 
found which were very rich in tin, and weighing from 50 to 150 
pounds each. The dike from which these boulders originated could 
not be located, but, judging from their appearance, it must be 
close by, and this locality is a very favorable one for prospecting. 
The schists have the general characteristic strike of the district, that 
is, N. 25° E. A quarter of a mile still further north, on Chestnut 
Ridge, munerous boulders carrying tin ore were observed. 

Chestnut Hill Vein... — A little to the east of the simimit of Chestnut 
Ridge, and about one-half mile from the Carpenter property, is wha* 
was formerly designated as the Chestnut Hill vein. A shaft was sunk 
here for a depth of 122 feet, following on a vein of tin ore that is 
reported to be 7 feet wide at a depth of 100 feet and to carry about 3 
per cent, of tin oxide. There are contradictory reports regarding 
what was found in this shaft, and judging from the material that is 
on the dump pile, there was not a great deal of tin ore taken out of 
the shaft. According to Mr. J. O. Horton, who had charge of this 
work, the shaft penetrated through the vein, and it was the intention 
to sink this shaft to a depth of 130 feet and then drive a cross-cut to 
the vein. No work has, however, been done here for about 10 years, 
and, as the shaft was full of water, nothing definite can be stated 
regarding the conditions existing in the underground workings. 

Ormond Property. — On the north end of Chestnut Ridge, on the 
property of Mr. J. J. Ormond, which is 3 miles northeast of Kings 
Mountain, considerable tin ore has been found in greisen boulders. 
It is reported that a trench made here encountered the greisen in 
place ; but this is now filled up, so that nothing of this vein could be 
seen. The boulders observed were very similar to those encountered 
on the southern end of Chestnut Ridge, and this is also a favorable 
place for prospecting. 

Ilovis Properly.- — Only a few fragments of tin have been found 
in the next one and a half or two miles from the Ormond locality; 
bnl on what is known as the White lot, which adjoins on the north 
the M. V. Ilovis place, boulders of greisen again become prominent, 
and these contain more or less cassiterite. On Mr. M. V. Ilovis' 
property I in ore is found in fragments and boulders of greisen near 
the mad and arc constantly being plowed up in the fields. In the 



THE TIN DEPOSITS. 29 

gutters alongside of the road considerable black sand has been con- 
centrated, consisting chiefly of cassiterite, magnetite and ilmenite. 

Ramseur Mill Property. — About a third of a mile northeast is the 
Ramseur mill property, where a large pegmatitic dike is outcropping. 
Considerable cassiterite has been found as float and a trench cutting 
across this pegmatitic dike exposed a portion of this rock that con- 
tained cassiterite. The ore occurred near the contact of the pegmatite. 
It was very rich, and is another one of the places along the belt that 
is favorable for more thorough prospecting. There is a great deal 
of ilmenite, which occurs principally in flattened plates, found scat- 
tered over the surface of the field and on a road within 100 feet of 
the trench from which the cassiterite was obtained. 

Jones Mine. — One of the most promising deposits of tin ore to the 
northeast of Kings Mountain is on the John E. Jones plantation, 
which is 7 miles northeast of Kings Mountain and 3^ miles a little 
northeast of Bessemer. A great deal of float greisen carrying cas- 
siterite has been found on a small hill about 100 yards from the house 
and a number of shafts and open cuts have been sunk on small masses 
of greisen that were observed out-cropping on the surface. One of 
these, which was 2 to 3 feet wide, had a strike of nearly N. 80° W. 
and is cutting at almost right angles the trend of the gneiss. This 
vein carried considerable tin ore, and, judging from a test made by 
panning down a sample taken from the vein in the shaft, it would 
carry in the neighborhood of 5 per cent, of cassiterite. This vein 
varies very greatly in the percentage of cassiterite that it contains, 
and a cross-cut made about 70 feet west of the shaft showed only a 
little cassiterite, and another cut 70 feet still further to the west did 
not show any cassiterite at all, and the vein contained considerable 
altered feldspar. The shaft is now partially filled with debris, but 
it is reported that it continued in ore to the bottom. As far as it 
could be examined, it still showed good tin ore. There is an area 
on the slopes of this hill and along the branch, making an area of 
about 200 by 300 feet in which cassiterite has been found, and would 
represent the alluvial deposits that are known at the present time and 
which will probably pay to hydraulic. During the winter of 1903 
and 1901 work was again begun on these deposits and the saprolitic 
rock and alluvium were being washed and concentrated in the stream 



30 THE TIN DEPOSITS. 

at the foot of the hill. Throughout nearly all the tin belt to the north- 
east of Kings Mountain the scarcity of water is a serious drawback. 

OTHER TIN LOCALITIES IN THE UNITED STATES. 

Oassiterite has been found at a number of localities throughout 
the United States, but usually in only small quantities and often 
simply as isolated crystals. 

Maine. — In Maine* cassiterite has been found very sparingly at 
Paris, Hebron, Winslow and Stoneham. At the two former locali- 
ties it has been found well crystallized and associated with the beau- 
tiful tourmalines for which these localities are noted. They occur 
in pegmatitic dikes which have been highly mineralized. At Wins- 
low, Maine, cassiterite has been found associated with quartz, mica 
and fluorspar in limestone. They occur in thin seams one to two 
inches in width, sometimes following, at others cutting across the 
stratification. 

New Hampshire. — In New Hampshiref cassiterite has been found 
in some quantity in the town of Jackson and at Lime, in both places 
being associated with iron, copper and other sulphides. 

Massachusetts. — At Chesterfield and Goshen, Massachusetts,^: cas- 
siterite has been found associated with tourmaline in pegmatitic dikes 
similarly as at the Maine localities, but it is not as well crystallized. 

Virginia. — The occurrence of tin in Virginia was described by Mr. 
Arthur Winslow§ in 1885, and later by Mr. Titus Ulkel in 1893. 
This tin area extends along the eastern edge of Rockbridge county 
in the line of the Bine Ridge Mountains from a few miles north of 
the James River Gap to about the north line of the county. Cas- 
siterite lias been found at a number of places in this area, but the 
greatesl amount of ore was found along the upper waters of Irish 
creel? in I lie northeastern corner of the county. There is one prop- 
erts thai has been developed to some extent, and this is known as 
the Cash mine. The greisen veins in which the tin occurs traverse 
the granite in all directions ami arc dipping at, very steep angles. 



•Trans. Am. Inst. Min.. Enjr., Vol. 1. 1H7I-73, p. 373. 
I l i.m, a Mineralogy, 6th Edition, 1892, p. 235. 

Dana Mineralogy, 6th Edtion, 1892, p. 235. 

En« and Min. Jour., N'<v. 7. 1885. 
' 1 1 S. Geol. Survey, Min. Res., 1893, p. 180. 



THE TIN DEPOSITS. 31 

The width of these veins is usually from 8 to 12 inches, though some 
were observed that were several feet in thickness. The cassiterite 
is occasionally concentrated into seams from 1 to 2 inches wide and 
is associated with pyrite and arsenopyrite, the rest of the gangue 
of the veins being composed of quartz and mica. The principal work 
was done here about twenty years ago, and a concentrating mill 
was erected on the property and about 290 tons of rock were tested. 
It is reported that about 2,400 pounds of tin concentrates were 
shipped to Boston, but that they only averaged about 43 per cent, 
of metallic tin, due to the concentrates being contaminated with 
arsenopyrite and ilmenite. There was not sufficient work done on 
the property to definitely determine whether or not there existed a 
commercial deposit of cassiterite. 

Alabama. — Tin has been found in Coosa county, Alabama,* near 
Brockford, associated with tourmaline, biotite and tantalite. 

South Dakota. — The South Dakotaf tin deposits have attracted 
the greatest attention, and a great deal of work has been done on the 
deposits in that State in an attempt to open commercial bodies of 
tin ore. The deposits lie to the west and south of Custer and through- 
out what is known as the Nigger Hill District, which is west of 
Deadwood, extending down into Wyoming. The principal deposits 
that have been opened up are known as the Etta and Ingersoll mines 
about G miles east of Harney Peak and 20 miles from Rapid City. 
The occurrence of the tin at both of these mines is very similar, 
and a description of one would fit closely that of the other. At the 
Etta mine there is a granitic knob in the form of a conical hill, which 
is cutting through mica and garnetiferous slates, and is about 250 
feet high by 200 feet in its longest diameter and 100 to 150 feet in 
its transverse diameter, as measured across the outcrop. This mass 
of granitic rook has a somewhat concentric structure, the outer por- 
tions next to the slates being composed of a band or belt of dark- 
colored mica ; then a zone of very large spodumene crystals with 
albite, feldspar and irregular bunches of crystals of mica and albite. 
jSText is the greisen rock, which has cassiterite disseminated through 
it in small grains and imperfectly formed crystals. The centers of 
these granitic knobs are a mixture of quartz and feldspar. 

* Dana's Mineralogy, 6th Edition, 1892, p. 235. 

tW. P. Blake, Trans. Am. Inst. Min. Eng.. Vol. XIII, 1885, p. 691. 



32 THE TIN DEPOSITS. 

Texas. — Cassiterite lias been found in Texas* on the east flank of 
the Franklin Mountains, the southern extension of the Oregon or San 
Andreas Range, about 10 miles north of El Paso. These deposits 
were discovered in 1899 and had been prospected to a depth of about 
50 feet. The ore occurs in well-defined veins, which have a strike 
approximately east and west, which is nearly at right angles to the 
direction of the range and are dipping toward the north at very steep 
angles. There have been three veins discovered here, which have 
been exposed by pits and open cuts for several hundred feet along the 
strike. The veins occur in the granite and are considered by Mr. 
W. IT. Weedf to be the result of deep-seated agencies and that fur- 
ther exploration will develop well-defined tin veins. 

California. — The California^: tin deposits have also attracted more 
or less attention, and those in Riverside county in the Temiscal Dis- 
trict have been producers to the extent of probably about 40,000 
pounds of metallic tin. The principal mine in the district was the 
Cajalco on the San Jacinto estate. The tin deposits lie nearly in 
the center of a rudely semicircular area of granite about two miles 
in diameter, which is cutting the sedimentary rocks, quartzite, mica 
schist and conglomerate. In some instances porphyry is bordering 
the granite. Towards the outer edges of this granitic boss are numer- 
ous dikes of very fine-grained granite, consisting almost entirely of 
quartz and orthoclase feldspar in interlocking grains. This semi- 
circular area of granite and portions of the adjoining porphyry have 
been fissured in a general north-east and south-west direction, while 
almost innumerable lines have been subsequently filled with black 
vein matter. These veins are usually small, varying from a quarter 
to a few inches in thickness, but in one case, that of the Cajalco vein, 
it reaches an enormous width. The vein material of this main vein 
and the smaller ones consists for the most part of tourmaline and 
quartz. The larger veins are very irregular and sometimes appear 
to lie hnl bunches of vein matter in the granite. A few hundred feet 
northeasl of this wide portion of the vein it has narrowed down to 
or 8 feet. lint little development work has been done on this 
property to prove the existence of large bodies of tin ore. Most of 

• Bull. U. S. GeolofiT. Survey, No. 218, ]). 99. 

; ii, mi. 

Aim. .Jour, of Sei., Vol. IV. 1HD7. p. 89. 



THE TIN DEPOSITS. 33 

the money expended was on top of the ground in buildings, roads, 
etc. It is not at all improbable but that conservative development 
work would show tbe existence of a sufficient quantity of ore to make 
profitable mining. 

Another locality in California that is attracting some attention 
is on the west slope of the Santa Anna Mountains in Trabuso Canyon, 
Orange county. This property is now being developed, but it has not 
been definitely determined as to the quantity of tin that it contains 
or whether it is possible to make it a producer of this metal. 

Alaska. — Perhaps the most promising tin region in the territory 
of the United States, outside of the Carolinas tin belt, is that in 
Alaska,* near Port Clarence, in the York region. Cassiterite has 
been found as stream tin at a number of localities in this region, 
principally on Buhner creek, about 10 miles east of Cape Prince of 
Wales, and on the Anikovik river, about half a mile below the mouth 
of Buhner creek. Tin has also been found in place by Mr. Arthur 
J. Collier, of the United States Geological Survey. Its occurrence 
is similar to that of cassiterite from other localities,- and it is asso- 
ciated with fluorite, tourmaline and wolframite. Although undevel- 
oped, the indications are such that it makes a promising locality for 
further investigation as to its commercial possibilities. Stream tin 
has also been found at Copper river, about 125 miles northeast of 
Valdez, by Mr. A. W. Tibbitt of that town. 

Other States. — Other localities in the United States where stream 
tin has been found are in Crook county, Wyoming; near Dillon, 
Montana ; and at Jordan creek, near Booneville, Idaho ; but at none 
of these has there been any indication of the mineral occurring in 
commercial quantity. 

It will be seen from the above that thus far no profitable tin mining 
has been accomplished in the United States and that all the deposits 
are still in the prospective stage. Considering, however, the value 
of tin ore, the quantity of the metal that is used in the United States 
and its limited occurrence in other parts of the world, the Carolina 
tin deposits are well worthy of a thorough, systematic investigation 
as to their commercial value. In some instances it will be found that 



5 U. S. Geolog. Survey, Mineral Resources, 1900, p. 267. 



34 THE TIN DEPOSITS. 

a considerable portion of the cost of this development work will be 
paid for by the value of the cassiterite obtained. 

FOREIGN TIN LOCALITIES. 

Malay Peninsula. — The world's chief source of supply of tin is 
from the deposits on the Malay Peninsula,* which extend from the 
extreme southern end of the Peninsula northwestward for a distance 
of about 350 miles to the border of the Siamese possessions. Through- 
out this entire distance tin ore is found in more or less quantity, and 
it has also been reported to occur still further north into the posses- 
sions of Siam ; but up to the present time these latter deposits have 
been explored but little and nothing definite is known regarding their 
extent or commercial possibilities. 

Extending almost the entire length of the Malay Peninsula is a 
long, high mountain range, forming the backbone of the Peninsula, 
and it is only on the western slopes of this range that the tin ore has 
been found. Although tin has been found over such an extensive 
area in the Federated Malay States, it is only from a few districts 
that it bas been proved to be in commercial quantity. The State 
producing the largest quantity of tin is Perak, from which is obtained 
over one-half of the total quantity of tin obtained on the Peninsula, 
which in turn produces over half of the world's supply of this metal. 
The principal mining district of Perak is known as the Kinta, and 
tin's is the largest and most celebrated tin mining district in the 
world. Selangor is the second largest, tin-producing State on the 
Malay Peninsula, but its production is far below that of Perak. 
Other States from which small amounts are mined are Pahang, Negri 
Sembilan and Johor. This latter State is at the extreme end of the 
Peninsula. 

The tin ore is obtained almost entirely from the alluvial deposits, 
although deposits of tin have been discovered in granite and also in 
limestone. Up to the present time, however, these latter deposits 
have QOl proved to I"' profitable mining. The cassiterite is found 
in these alluvia] deposits, sometimes scattered through it from top to 
hot loin, IhiI iii most, cases, however, there is an overburden of soil from 
1 to 10 feel, which is almost entirely barren of any tin ore. The 



Jour. Geol., Vol. XI, No. 2, L908, p. 185. 



THE TIN DEPOSITS. 35 

most profitable alluvial deposits occur at the foot of the mountains. 
Higher up the mountain slopes it has been found • richer, but on 
account of the very small area over which these extend, they do not 
make profitable mining like the more extensive areas lower down. 
The tin in the alluvium has undoubtedly been derived from the 
neighboring rocks, granite and limestone. It occurs in the granite 
in the form of small pockets or veins from which stringers are often 
running out, intersecting each other in various directions, forming 
often a network of tin-bearing seams. The principal minerals asso- 
ciated with the cassiterite are quartz, tourmaline, fluorite and pyrite. 
Where it is found in the limestone it is usually along the zone of 
fracturing, either as an impregnation or as lenses, or irregular 
pockets. Seams carrying tin ore are often found following the cracks 
in the rock and running out into it for some distance. The minerals 
associated with the cassiterite found in the limestone are for the most 
part sulphides, there being large quantities of pyrite and arseno- 
pyrite with smaller amounts of the copper minerals, chalcopyrite and 
bomite. 

The general method of working these deposits is by open cuts or 
large pits, but in those cases where the overburden is too deep, shafts 
are sunk until the tin-bearing strata are encountered. On account 
of the difficulty of taking care of the water, the pits and cuts that are 
made by Chinese are usually shallow, seldom averaging over forty 
feet deep. After the tin-bearing alluvium has been brought to the 
surface, which has been accomplished by means of small baskets hung 
on both ends of a stick and suspended on a man's back, it is dumped 
into long wooden troughs, in which there is a stream of running 
water. If there is much clay in the alluvium, the material is stirred 
with shovels and hoes to separate the tin ore. The materials are 
carried by the water from the troughs into sluice boxes, where the 
tin ore and other heavy minerals sink to the bottom, while the lighter 
materials are carried away by the stream. These sluices vary from 
a few feet to several hundred feet in length, according to existing 
conditions, and are made of wood. Occasionally cuts are made in 
the sandy clay of the region, which are used in place of the wooden 
troughs. After this operation has been carried on for several hours, 
the flow of water is stopped and the material that has been concen- 



36 THE TIN DEPOSITS. 

trated on the bottom of the sluice boxes is still further concentrated 
by panning in flat wooden bowls, which in shape are similar to the 
ordinary iron gold-pan. The concentrates are still further purified 
by picking out by hand the magnetite and other heavy minerals. The 
final product contains from 69 to 73 per cent, metallic tin. 

Formerly all the tin ore was smelted at local works in the various 
districts, but now it is nearly all treated at the smelters of the Straits 
Company, located at Singapore. The agents of this company are 
in constant touch with all the producers of tin so that they prac- 
tically control the output of tin ore from the various mining districts. 
On account of a high export tax which has been placed by the Govern- 
ment on tin ore, it is impracticable to attempt to smelt these ores 
elsewhere. Before this export tax was imposed, a company had been 
organized in the United States whose object was to erect a smelter and 
to treat tin ores. Their source of supply was to be mainly from the 
Malay Peninsula. On account, however, of this export tax the 
project has failed. 

Bank a and Billiton. — On the Islands of Banka and Billiton, which 
are 200 to 300 miles southeast of the southern extremity of the Malay 
Peninsula, is located the second largest tin mining district of the 
world. These islands are owned by the Dutch, and the Banka mines 
are worked by the Government, while those on Billiton are operated 
by an independent company. The production from Banka is over 
three times that from Billiton, and is probably due to the Govern- 
ment having supervision of the mines. The combined Banka and 
Billiton mines produce a little over one-fifth of the world's produc- 
tion of tin. The occurrence of the tin on these islands is very simi- 
lar to that on the Malay Peninsula. 

Sumatra. — On the Island of Sumatra, in the District of Siak, tin 
has been found, but on account of the inaccessibility of the district 
and of the internal troubles between the natives and the Dutch Gov- 
ernment, these, deposits have not been thoroughly explored. 

Bolivia. The Bolivian deposits* are the third largest producers 
of tin, their output being about one-tenth of the world's production. 
Tin lias been found over a wide area along the eastern edge of the 
Bolivian table land, which forms the extreme western part of Bolivia, 
for a distance of about 300 miles in a north and sonlh direction, 
* Mir., [nd., L892, p 543. 



THE TIN DEPOSITS. 37 

across the Departments of La Paz, Oruro and Potosi. There are 
a number of localities in each of these Departments where tin occurs 
in paying quantities and is being mined at the present time. The 
principal deposits which are known are Huayna, Potosi, Totoral, 
Berenguela, Tres Cruces, Sayaquiri and Quisma-Crur in the De- 
partment of La Paz ; Huanuni, Colquiri, Negro Pabellon, Antigura 
and Morococala in the Department of Oruro ; and Llallagua, Apa- 
cheta, Chorolque and Tazna in the Department of Potosi. These 
deposits are at an altitude of from 13,000 to 15,000 feet above sea- 
level, and some of them, as those in the great Chorolque Mountain, 
are 17,000 feet high. The tin ore occurs in veins which are dipping 
at angles from 50° to 70° and vary in width from a mere seam to 
25 or more feet in width. These veins are found cutting through 
the metamorphic shales and also in the adjacent igneous rocks. The 
tin minerals usually occur in streaks in the veins, the gangue being 
made up largely of silica, with some feldspar, the latter being more 
or less kaolinized. As a rule, however, the gangue matter is solid. 

It has been estimated that the ores in Huanuni and Avicaya will 
average from 10 to 12 per cent, metallic tin. The ores are crushed 
either by stamp mills or by crashers and rolls and then sieved. 
The pulverized material is then passed through hydraulic separa- 
tors, slimes or lighter material being carried off at the top into 
settling tanks, after which it is treated in round buddies and on 
Wilfley tables. The coarser material from the hydraulic separators 
is classified in trommels and concentrated in automatic jigs. The 
concentrates are further treated by washing in sieves, after which 
they are dried and sacked for export. Some of these deposits have 
been worked to a depth of 300 to 400 feet, but it has not been proved 
definitely as yet to what extent they will prove profitable. 

England. — The Cornish tin mines of England* are perhaps the 
most widely known of &nj of the deposits of this metal, and were 
undoubtedly the first to produce tin. For over 2,000 years these 
deposits have been furnishing England with tin, and are still 
producing at the rate of 4,000 tons or more per year. The allu- 
vial deposits were formerly worked very extensively, but at the 
present time it is from the under-ground mines that the tin ore is 



* Trans. Min. Ass. and Inst, of Cornwall, Vol. Ill, Parts 1 and 2 ; and Mineral Industry, Vol. I. 
1892. p. 439. 



38 THE TIN DEPOSITS. 

obtained. The veins occiir principally in granite overlain with a 
slate, and are dipping at high angles to nearly vertical. Cutting 
both these rocks are a series of quartz-porphyry dikes, while the veins 
carrying the tin traverse all three of these rocks, thus showing that 
they were formed at a later period than any of the others. Where 
these veins are found cutting the slates they are not apt to carry very 
much tin, but more copper; while on the other hand, as they penetrate 
into the granite the copper gives out and they become rich in tin. 
While there is a main vein or leader which can be constantly followed 
with a permanent dip and strike, there is constantly branching out 
from this stringers and seams which penetrate into the adjoining 
country rock, and sometimes are so large that they exceed in extent 
the main lode. Then again, portions of the country rock itself are 
impregnated with the tin ore, so that there is a gradation from the 
ore to the barren country rock. This is true of the veins in the 
slate and also in the granite. Occasionally a lead will be opened up 
that has a slate for one wall and a granite for the other. These are 
the deepest workings of any in the history of tin mining, and they are 
now down over 2,000 feet below sea-level. The rook as it is obtained 
from the mine is usually crushed in stamp mills, the larger lumps 
'being broken by hammers. It is crushed in these mills fine enough 
to pass through a 40-mesh screen, from which it is carried by water 
to the concentrating room, where various appliances are utilized to 
effect this concentration. 

Australia: — The production of tin from Australia is now begin- 
ning to exceed that from England, and these deposits are taking a 
prominent place in the world's production of this metal. It is mined 
in New South Wales and Queensland and on the Island of Tasmania. 
It has also boon found in Victoiia; but its production in this latter 
province is very small. In Western Australia tin was discovered in 
the latter part of 1S88 near Bridgetown, and the alluvial deposits 
have been worked on a small scale; but until a larger water supply 
can be secured they cannot be developed as fully as the percentage of 
tin warrants. The Government has recently erected a tin-dressing 
plan! as an aid to the development of the tin mining industry in 
ili.'il section. 

In New South Wales the principal mining sections are at Emma- 



THE TIN DEPOSITS. 39 

ville and Tingha, in the northern part of the colony. At Tingha, 
Iiardinge comity, the alluvial deposits are worked by dredging, and 
a considerable area of rich ground has been shown to exist in the beds 
of Coke's creek and tributaries. The largest amount of work has 
been done in the vicinity of Emmaville, Clive county. Other locali- 
ties in New South Wales where tin deposits are being developed are. 
at Silent Grove in the Deep Water District and at a number of places 
in the Broken Hill District. 

The. tin deposits of Queensland are in the Herberton District, 
which comprises an area of about 750 square miles, and this district 
produces about one-half the tin obtained in Australia. Irvinebank 
is the principal center of this mining district, and in its vicinity are 
two of the largest producers, the Vulcan and Tornado mines. Other 
districts in Queensland which are producing small amounts of tin are 
Cockestown, Kangaroo Hills, Palmira and Stanthorpe. Nearly 
all the tin that is mined in the Herberton District is from veins, 
while that from the other districts is obtained from alluvial deposits. 

Tasmania. — The tin deposits of Tasmania* were discovered at an 
early period in the history of this colony, but not until 1872 were 
any profitable deposits found. In that year was discovered the great 
Mt. ISTaschoff, which has continued to be the largest producer in 
Tasmania. While at first mining was confined entirely to the allu- 
vial deposits, now the greater part of the tin is obtained from deep 
mining on the veins. 

Mexico. — In Mexico there are numerous localities where tin has 
been found, and it offers a promising field for prospecting for this 
metal. The principal deposits are at Potrillos in the State of Dur- 
ango ; at Sain Alto in Zaeatecas ; in the Santa Mario del Rio District 
of Sain Luis Potosi. This belt, which extends in a northwest direc- 
tion, produces each year a few hundred tons of tin, all of which is 
used in Mexico. Both veins and alluvial deposits are worked ; but 
at the present time the most of the production is from the latter 
deposits. 

Other Localities. — Tin has also been found and worked in certain 
parts of China, but little is known regarding its occurrence or the 
amount of production. There is also a small amount produced in 



*Min. Ind., 1892, p. 451. 



40 THE TIN DEPOSITS. 

Japan and Burmah. Tin deposits have been reported from Peru and 
Chili in South America, but as yet have not become producers of this 
metal. In Europe there are small amounts of tin that have been 
reported from Spain, Portugal, Germany and Austria, but the com- 
bined production from these countries is very small as compared with 
the world's production. 

There has been a small amount of tin ore produced in Swazieland, 
South Africa. The deposits from which the ore was obtained are 
on the eastern slope of the Drakensberg Mountain, about 15 miles 
from the Transvaal border. 

ORIGIN OF THE TIN ORE. 

It is the authors' idea regarding the origin of the tin ore found 
in the Carolina belt, that it is due partly to the direct separation or 
recrystallization of the cassiterite from the molten pegmatite magma, 
but it is also due to a fumarole action, resulting from the escaping 
vapors during the crystallization of the molten magma of pegmatite 
intruded into the schists and gneisses in the form of dikes, which in 
turn had thrown off apophyses and lens-shaped masses or "augen," 
that have been subjected to the same reactions as the main mass of 
pegmatite. 

HISTORICAL. 

In discussing this method of origin of the tin ore, consideration 
has been given to the theories advanced for the origin of other occur- 
rences throughout the world, and there are given first short statements 
regarding these. 

Regarding the origin of the tin in the granites in the Ivinta District 
of the Malay Peninsula, Mr. P. A. F. Penrose* says: 

"In the granite, the occurrence of the cassiterite in veins, stringers, 
lid works, etc., along lines of fracturing, are strong evidences of 
aqueous deposition of the ore; while (he occurrence as an impreg- 
nation in the rock where no marked Assuring occurs, may be due 
either to segregation during a more or less molten condition of the rock 
or to aqueous concentration in a solidified rock. It is possible that 
the I in was originally a disseminaled constituent of Hie granitic rocks ; 
and in places its concentration may have been due to segregation from 
a molten mass, but there can be no doubt that some of the concentra- 

"Jour. of Geol., Vol. XI, No. 2, 1904, i>. L49. 



THE TIN DEPOSITS. 41 

tion, as at present seen, was due to water action after the solidification 
of the rock." 

Mr. W. II. Weed,* in discussing the El Paso, Texas, deposits, says : 

"The veins exhibit the usual characters of the European tin veins, 
notably those of Cornwall, England, their clearly-defined fissures 
showing a central core of lead or coarse quartz,i sometimes containing 
tin ore, and flanked on either side by altered rock, in which the tin 
ore replaces the feldspar of the granite. Where this metasomatic 
replacement is complete, the ore shows a mixture of cassiterite with 
or without wolframite and quartz. Where the replacement is only 
partial, the greisen ore fades off into the unaltered granite. A cross- 
section of the vein shows, therefore, the same phenomena seen in Corn- 
wall. The central mass of quartz corresponds to the 'leader' of the 
Cornish veins. It is composed of massive, coarsely crystalline quartz, 
sometimes showing comb structure, and it is clearly the result of the 
filling of the open fissure by quartz. The adjacent ore-bearing mate- 
rial is a replacement deposit in which the mineral solutions have sub- 
stituted for the feldspar of the granite by metasomatic action ; in other 
words, the main mass of the ore occurs alongside of a quartz vein, 
and is due to the alteration of the granite forming the walls of the 
fissure. In general, the ore passes into the granite by insensible 
transition, and there are no distinct walls." 

Dr. H. W. Fairbanks,* in discussing the large Cajalco vein of 
California, says : 

"The deposits have evidently been formed in fissures through a 
gradual replacement of the granite walls. Judging from an exami- 
nation of the seam-like veins, the silicates appear to have been at- 
tacked easier and removed first, In places the larger veins seem to 
blend into the granite, and it was at first thought that some of the 
quartz might be a remnant of the granite, as it is rarely, if ever, seg- 
regated in bunches. A microscopic examination showed that this 
view was undoubtedly false, as the grains interlock in a different 
manner from those in the granite, and in addition contained fluid 
and liquid inclusions. The relative proportions of quartz and tour- 
maline in the Cajalco vein are so constant that it represents a uniform 
appearance. * * * The bunches in these veins, and especially 



*Bu11. U. S. Geol. Survey, No. 213, 1902, p. 100. 
*Am. J. Sci., Vol. IV, 1897, p. 41. 



42 THE TIN DEPOSITS. 

the enormous one forming Cajalco hill, could have been formed in 
no other way than by replacement, although it is difficult to conceive 
of its having taken place on such a large scale." 

The origin of the cassiterite occurring in the small veins in rhyo- 
lite tbat are found at Sain Alto, Mexico, is referred to by the Geolog- 
ical Institute of Mexico,* which makes the following statement : 

"The veins appear to have been formed from lines of fracture 
produced by contraction due to cooling and to have been filled by 
direct emanation. The associated minerals are hematite, topaz, and 
in some places durangite — that is to say, two minerals which contain 
fluorine, thus bearing evidence of the identity of the agent employed 
by nature in bringing tin to the surface in the same state of combina- 
tion and at different and widely separated geological periods, and 
always, be it remembered, in the most acid rocks of the two series of 
eruptions ; in the ancient series tin appears in granite containing 
white mica, while in Mexico, where the most impure emanations of 
tin have taken place, it appears in rhyolite of the upper Tertiary." 

Dr. Albert R. Ledoux,f in discussing the deposits of tin in North 
Carolina, says: 

"Having secured permission to investigate the properties, we exam- 
ined them by open cuts and shafts in perhaps half a dozen places for 
an extent of, occasionally at least, 2 miles north and south, and I 
have also visited openings which others have made since we began 
operations, at a distance of 6 or 7 miles from the village. We also 
put clown a number of holes with a diamond drill for the purpose 
of determining the character at considerable depth. The drill, I 
may say here, shows these greisens apparently to be large, irregularly 
bedded masses, their vertical extent being in no way determinable by 
their appearance on the surface. They are unquestionably bedded 
veins, although occasionally, when cut by trap dikes or from other local 
causes, taking on the appearance of true fissure veins. Our deepest 
hole lias shown layers of schist and greisen, greisen and slate, slate 
and greisen, etc., indefinitely." 

Professor William l!lake,:|: commenting on the origin of the tin ore 
found in the Black 1 1 ills, says : 

•Hull, tn, No-:. 4, 5, 6, 1807, pp. 284, 285. 
rEnsr. and Min. .lour.. Vol. 48, L889, p. 521. 
I ran km In t. Min. Enff., Vol. XIII, L885, p. 695. 



THE TIN DEPOSITS. 43 

"In the numerous tin veins and tin-ore-bearing granitic dikes of 
the Black Hills tin region, the phenomena of occurrence and associa- 
tion indicate that all of the minerals of the dikes — the quartz, feld- 
spar, spodumene, mica, beryl, columbite, tantalite, phosphates, and 
other associates of the cassiterite, were contemporaneous in origin. 
The tin-stone is apparently as much a part of the mass as the mica or" 
quartz. It was, to all appearance, present when the whole mass 
assumed its crystallization. All the constituents of the dike appear 
to have crystallized from a semi-fluid or pasty magma, in which the 
elements were free to arrange themselves from one side of the dike 
to the other and to crystallize out slowly. This is indicated in several 
ways, but strikingly by the gigantic crystals of spodumene stretching 
across the mass at the Etta, in straight lines, for 20 to 40 feet, in the 
midst of quartz, feldspar and tin ore." 

The occurrence of the South Dakota tin ores is unlike that which 
would be expected to be seen in narrow fissures that have been filled 
gradually by solutions depositing layer after layer on each side of 
the fissure until the same becomes filled up. There is also a decided 
lack of any signs of infiltration or of alteration or of replacement of 
the minerals by tin-stone, and thus this has the appearance of being 
one of the original constituents of the granite. 

Mr. J. H. Collins,* in commenting on the Cornwall cassiterite, 
states that it occurs as 

"(1) pebbles, rough masses or grains (stream tin) ; 

(2) filling of definite fissures in granite, slate and porphyry; * * 

(3) the filling of minor joints and shrinkage cracks (the latter, 
when numerous, form stock works) ; ■ * * * (4) cementing ma- 
terial for conglomerates and breccias in fissures; * * * (5) as 
a constituent of ancient breccias occupying the fissures ; * * * 
(6) as a minor constituent of granite, porphyry and in tourmaline 
schist; * * * (7) as a pseudomorphous replacement of feld- 
spar, quartz, etc; * * * (S) as pseudomorphous replacement 
of organic structure." 

Professor J. F. Kemp,f in speaking of the deposits of tin ore in 
a general way, says that they have been especially developed along 
the contacts of granite intrusions. 



*Min. Mag. London, Vol. IV, ]8S0. 

f Ore Deposits of the United States, 1900, p. 69. 



44 THE TIN DEPOSITS. 

"Granite, as is well known, is the most potent of all rocks in bring- 
ing about contact metamorphism. It seems to be especially rich in 
mineralizers, and as its great, intruded, batholitic masses slowly crys- 
tallize, they emit boracic, hydrofluoric and other vapors in exceptional 
volume. Wall rocks are greatly corroded and charged with tourma- 
line, fluorite, axinite, topaz, fluoric micas and cassiterite. Pegma- 
tite dikes or veins are sent off as apophyses, and are charged with the 
same association of minerals. If the walls themselves are granitic 
in composition, the feldspar becomes greatly corroded, and may be 
replaced by quartz and fluoric micas with more or less cassiterite. 
Pegmatites consisting essentially of the same minerals are also pro- 
duced, and both varieties are called greisen, and are recognized as the 
characteristic gangue of tin ores the world over." 

Again, on page 442, Professor Kemp says: 

"Cassiterite occurs in small stringers and veins on the borders of 
granite knobs or bosses, either in the granite itself or in the adjacent 
rocks, in such relations that it is doubtless the result of fumarole 
action, consequent on the intrusion of the granite." 

Cassiterite was first made synthetically by D'arubree* by decom- 
posing the vapors of the bichloride of tin (SnCl 2 ) with steam at high 
temperature, the products obtained being small crystals, identical 
in form with the natural cassiterite. Henri Sainte-Clair Deville and 
Caronf produced artificial cassiterite or tin oxide (SnO a ) by a simi- 
lar method, but using vapors of the fluoride of tin instead of the 
chloride. These crystals of tin oxide which were obtained were also 
identical in form with the natural product. 

EVIDENCE BEARING ON ORIGIN. 

This synthetical production of tin oxide, identical in composition 
and crystallization with natural cassiterite, offers a clue to the origin 
of some of the deposits of this mineral, and is strong evidence that 
considerable of the tin oxide found in nature has been produced 
by the action of vapors of tin chloride or tin fluoride on the masses and 
dike of pegmatite veins by the metasomatic replacement of the feld- 
spar with tin oxide. This lias more probably beer accomplished by 
the action of the fluoride ; for of the associated minerals that are found 

"Synthe le dea Mincraux el edes Roches, by Fouque et Michellevy, 1883. 
i ,oc, cit. 



THE TIN DEPOSITS. 45 

with the cassiterite (tin ore), those that contain fluorine are common; 
while seldom, if ever, are any of the chlorides or minerals containing 
any appreciable amount of chlorine found. The hot steam vapors 
which would be present, especially along the contact of these pegmatitic 
masses and dikes, with the other country rock would react with the 
stannic fluoride (SnF 4 ) in the formation of the tin oxide (Sn0 2 ), 
setting free probably hydrofluoric acid (HF), which would readily 
attack any of the silicates, replacing them, to some extent at least, 
with the tin oxide and forming the silicates containing fluorine and 
also producing some fluorite, calcium fluoride. This would also 
account to some extent for the honey-comb appearance that is often 
observed in the quartz carrying tin. 

As has already been stated, there are three occurrences of the cassit- 
erite in the Carolina belt: (1) As lenses and veins in the schist whose 
strike and dip correspond approximately to that of the schist; (2) 
the more clearly defined veins, which are cutting across the lamination 
of the schist or gneiss; and (3) veins occurring in gneiss, as those at 
the Ross mine. All of these veins are considered as belonging to the 
same pegmatitic formation, and to have been formed at the same time. 
There is one large and almost continuous dike which has been ob- 
served, which can be traced almost continuously from a short dis- 
tance above Kings Mountain nearly to Grover, JSTorth Carolina, a 
distance of 7 miles, varying in width from 25 feet to nearly 
200 yards. These pegmatitic dikes, which have for the most part 
resisted alteration and erosion better than the surrounding schists, 
outcrop prominently and can thus be readily traced across country. 
This pegmatitic material occurs as a series of lenticular-shaped masses 
breaking through the schist approximately paralleling the main dike 
of pegmatite. These masses of pegmatite are separated from each 
other by schist and often pinch out along the strike. Before, how- 
ever, they have given out entirely another lens is apt to be encoun- 
tered. 

This occurrence is represented in Tig- 6, which shows the irregular 
mass of the main pegmatitic dike parallel to which are what seem to 
be a series of the lenses of pegmatite, which are connected with each 
other by very narrow seams of pegmatitic material As this main 
mass of pegmatite was intruded into the schist the apophyses, which 



46 



THE TIN DEPOSITS. 



were thrown off from the main mass and forced their way up between 
the laminations of the schist, would have a tendency not only to form 
a series of lenses in a vertical direction, but also horizontally, and 
this latter series would, upon erosion, be exposed on the surface simi- 
larly as represented in Fig. 6. 




Fig. 6.— A Horizontal Cross-section of a Mass of Pegmatite Intruded into Schist. 

In general, where pegmatitic dikes are cutting through schists, fol- 
lowing closely the strike of the laminations of the schist, they are apt 
to be irregular and to throw off numerous apophyses, which ramify 
between the laminations of the schist, giving the pegmatite a A^ery 
irregular and peculiar outline. In Fig. 7 (p. 47) is an ideal vertical 
cross-section of such a mass of pegmatite intruded into the schistose 
rock where the strike of the dike is approximately that of the schist. 
Such a mass of pegmatite, upon erosion, would appear on the sur- 
face to be made up of a series of separate masses of pegmatite, while 
in reality I hey would all be parts of the same dike. Such an appear- 
ance is illustrated in Fig. 8 (p. 47), which shows ideally a horizontal 
cross-section of the same, mass of pegmatite which is illustrated in 
Fig. 7, if this had been eroded to line A A. The apophyses 1, 2 and 3 
of Fig. 7 would appear on the surface as distinct and separate masses 
of pegmatite, 1, 2 and 3 of Fig. 8, and which apparently have no 
connection whatever with the main mass of pegmatite, 4 of Fig. 8 
being separated from it by the schist. 

Such occurences of pegmatite showing similar irregularities in 
structure have been observed in the northern part of North Carolina 



THE TIN DEPOSITS. 



47 




Fig. 7.— Ideal Vertical Cross-section op an Irregular Mass of Pegmatite 
Intruded into Schist. 




Fig. 8.— Ideal Horizontal Cros^-section of a Mass of Pegmatite in Schist. 



4S THE TIN DEPOSITS. 

in Mitchell and Yancey counties, where these dikes contain commer- 
cial quantities of mica, and mining is heing carried on for this min- 
eral. At the Burton and White mica mine, Mitchell County, an 
occurrence of pegmatite was observed of which Fig. 6 would be an 
almost exact reproduction. This is also true as the pegmatitic forma- 
tion is followed northeastward, all the dikes or veins being of rather 
narrow width until the Ramseur Mill property is reached, where a 
mass of pegmatite was observed 200 feet wide. 

Where the pegmatitic dikes ai*e cutting across the strata of the sedi- 
mentary rocks they are more even in width, and are usually occur- 
ring as a single distinct dike. In many cases these cross dikes are 
in the vicinity of the amphibolite dikes, and are approximately par- 
allel to them, and they may have followed a fracture formed at the 
time of the intrusion of the amphibolite. More rarely the pegmatitic 
dikes are cutting across not only the schist but also the amphibolite. 
The fluorine minerals that have been found associated directly with 
the tin ore are tourmaline and a fluorine mica. There has also been 
a considerable tourmalinization of the schist to the east of these peg- 
matitic dikes. Where the Avail rocks do not contain any feldspar 
they are not as apt to be affected by the action of the vapors as where 
the feldspar forms a prominent constituent of the rock. 

After the intrusion of these pegmatitic dikes, and as they began 
to crystallize, they were giving off boracic, hydrofluoric and other 
vapors, which corroded the wall rocks, reacting on the minerals pres- 
e?it in them, especially if they happen to be feldspars, and charging 
these wall rocks with tourmaline, fluoric micas, etc. 

There has bceu thrown out from the main mass or dike of pegmatite 
apophyses of the same material, which are also charged with these 
vapors and gases, which react in the same way as in the larger mass. 
Thus, where there is a large mass of pegmatite, the mineralization 
is along the borders of this and in the Avails of the adjacent rocks and 
in the apophyses and lens-shaped masses thai have been thrown off; 
while there is hnl Little change within the main mass of the pegmatite 
itself. In this way is formed the tourmaline that is ohserved so 
abundantly in souk; of the rocks adjoining the pegmatite. There 
was no occurrence observed where; the rocks were impregnated so 
abundantly that il could be called a tourmalinization of the wall rock. 



THE TIN DEPOSITS. 49 

The tourmalinization that has taken place in the Carolina field has 
all been east of the tin belt. 

Where the pegmatites are cutting gneisses containing considerable 
feldspar, the reactions of the hydrofluoric and other acids have been 
spent in some degree on this feldspar as well as on the feldspar of the 
pegmatitic dike itself. Thus, in these veins, as would be expected, 
there is more or less feldspar associated with the tin. Where these 
dikes have cut through schists, the original feldspar of the dike would 
be apt to be pretty thoroughly replaced by other minerals, as tourma- 
line, cassiterite, etc. ; as this mineral would be acted upon more read- 
ily than any of the others. Thus, in the tin veins cutting the schists, 
the vein material consists almost entirely of quartz, mica and tin, the 
two latter minerals representing, at least in part, replacement pro- 
ducts of the feldspar. 

There was not observed in any of the veins examined any indica- 
tion of a ribbon structure or any other structure that resembled the 
filling of narrow fissures by depositions from solutions from the sides 
of the fissure. 

The cassiterite occurs more or less crystallized in a matrix of quartz 
and mica, with occasionally feldspar. Where the dikes are very 
small it is rather evenly distributed throughout the vein, but where 
it occurs in the broad dikes or lenses it is more generally concen- 
trated toward one wall or the other. 

Many of the facts stated above would apply to the theory that the 
tin oxide was an original constituent of the igneous magma instead 
of being in the form of the fluoride ; and it may be that it has been 
partially formed in this manner, but still it seems as though the argu- 
ment was in favor of the fumarole action, resulting from the escaping 
vapors during the crystallization of the molten pegmatite magma. 
The absence of feldspar in the dikes which are cutting the schist and 
its presence in those cutting the gneiss, when all the dikes are of the 
same geological formation, are in favor of the latter view. 



50 THE TIN DEPOSITS. 

METHOD OF CONCENTRATING THE TIN ORE. 

ALLUVIAL DEPOSITS. 

At the present time the only tin ore that is being mined in the 
Carolina belt is that which can be treated hydraulieally, and consists 
of gravels, soils and saprolitic veins carrying tin. This material is 
washed similarly as in placer gold mining by first throwing the grav- 
els, etc., on a perforated plate to eliminate boulders, twigs, etc., and 
then bv running: the material throus'h sluice boxes. It is not neces- 
sary as a rule to use more than one or at most two boxes to save 
all the tin. These sluice boxes are about 8 feet long by 20 inches 
wide and 20 inches deep. There are two men required to operate 
each of these boxes, one to charge the gravel on to the perforated 
plate, which is fastened on to the upper end of the box, and the 
other to work the material in the sluice boxes up and down so as 
to permit the lighter materials to be carried off by the water. These 
boxes are usually cleaned up at the end of each day and the concen- 
trates dried. In some instances a very pure tin concentrate has been 
obtained that did not require any further refinement. In the South 
Carolina portion of the belt concentrates are apt to be diluted with 
monazite and garnet, while in the North Carolina portion of the belt 
the principal accessory mineral is generally ilmenite. 

It may be found advantageous, however, to run the concentrates, 
after they have been dried, over a magnetic separator in order to 
remove any ilmenite or magnetite that may happen to be present, and 
also by this same process any wolframite, garnet, or even monazite, 
that is present can be removed. The Wctherill magnetic separator 
could be used very advantageously for this purpose. 

Thus far there has not been observed in the concentrates any sul- 
phides or arsenides in sufficient quantity to detract from the value of 
these concentrates, and which, if present in any amount, would make 
ii necessary to roast the ore to eliminate the sulphur and arsenic. If 
these were present, the magnetic separator could be so adjusted as to 
undoubtedly remove al leasl the iron sulphides. 

Sluicing is being carried on al flic present lime at the Koss mine, 
near Graffrjey, S. C, and al I lie Junes mine, 7 miles northeast of 
Kincs Mountain. 



THE TIN DEPOSITS. 51 

Where sufficient water can be obtained and power developed, all 
of the soil, gravel, etc., can be readily washed down, often advanta- 
geously first through ditches cut into the ground and then into the 
sluice boxes, so that there is no necessity of handling the materials 
until the concentrates are taken out of the sluice boxes. As has been 
stated, however, in many sections of this tin belt water is rather 
scarce, so that a sufficient quantity could not be obtained for this pur- 
pose, and it would be necessary to excavate the gravels, soil, etc., and 
haul them to where they could be dumped on to the perforated plates 
above the sluice boxes. This is what is now being done at both the Ross 
and Jones mines. At the former mine, however, the stream which 
flows at the foot of the hill is being dammed, and it is expected that 
a sufficient quantity of water can be stored up so that the whole hill- 
side can be washed down without the necessity of hauling any of the 
material by wagon. 

At the Jones mine water is still more scarce, and it is questionable 
whether a sufficient supply can be developed to hydraulic the hillsides. 
The ore in the vein at this mine is composed largely of quartz and 
mica, making a rather solid ore, which would have to be crushed 
before it could be concentrated. It crushes, however, very easily, and 
the tin readily frees itself from the gangue minerals. 

At the Ross mine, on the other hand, where the vein is composed 
largely of kaolinized feldspar, it is readily broken down by water and 
requires no crushing. 

All of the ore that cannot be washed down by hydraulicing pro- 
cesses is being mined by means of open cuts, pits, etc. 

VEIN TIN ORE. 

In treating the ore, where it occurs in a hard vein formation, it 
will first be necessary to crush it. On account, however, of the posi- 
tion of the tin in the vein, it will often be found that the ore can 
readily be hand-sorted as it comes from the mine, so that a considera- 
ble concentration can be made before the ore goes to the crusher, thus 
eliminatina; a great deal of waste material which otherwise would 
have to pass through this machine. The ore will crush very readily, 
and as a rule the cassiterite separates itself very easily from the 
gangue minerals, so that it is not necessary to crush the ore to very 
fine sizes. This can be accomplished either by running the ore through 



52 THE TIN DEPOSITS. 

a crusher and stamp mill and then passing the crushed product over 
Wilfley concentrating tables or by using a crusher and rolls and then 
running the crushed ore on to concentrated tables or on to ordinary 
jigs. In this way a very pure tin concentrate will be obtained, which 
will be freer from accessory minerals than that obtained from the 
placer deposits ; for, as has been stated above, there are but very few 
minerals directly associated with the tin in the veins. 

ECONOMIC VALUE OF THE CAROLINA TIN DEPOSITS. 

The practical question that is at once raised regarding the occur- 
rence of tin in the Oarolinas is whether it will pay to work these 
deposits. There is no question whatever but that the alluvial de- 
posits, like those at the Ross mine, will pay to work and give large 
returns on the amount spent in obtaining the tin concentrates. These 
deposits, however, are carrying from 12 to 40 or more pounds of 
cassiterite to the cubic yard. A large proportion, however, of the 
alluvial deposits throughout the whole belt will not carry more than 
a few pounds of cassiterite to the cubic yard, which would mean from 
1 to 4 pounds of metallic tin. With tin valued at 25c, this 
would mean that the alluvial deposits would be worth from 25c. 
to $1 per cubic yard, and would very probably pay to work, 
if operated on a large scale, even when the cost of pumping water 
is taken into consideration, especially as the conditions for mining 
in the Carolinas are so favorable. Sluicing could be carried on 
with but few days of interruption throughout the entire year 1 ; 
and then labor is cheap, miners receiving from 75c. to $1.25 per 
day. Cord wood can be delivered for $1.50 to not over $2 per 
cord, and consisting of the best firewood, being a mixture of oak 
and pine. Timber and other supplies can also be obtained at very 
reasonable prices. The greatest expense will be the installation of 
the pumping plant and storing of water for hydraulicing. 

Regarding the economic value of the tin ore occurring in the veins, 
this is a little more problematic. Still if the veins contain but one 
per cent, of metallic tin, this would make an ore worth $5 per ton and 
would undoubtedly make a profitable proposition, if the deposits can 
be hown to contain a sufficient quantity of ore, so that a plant could 
be installed that would be capable of treating about 500 tons of ore 



THE TIN DEPOSITS. 53 

daily. Of course before there should be any expenditure made to 
equip any of the properties with machinery for treating the ore on 
a large scale further explorations and tests should be made. 

EXTRACTION OF TIN FROM ITS ORES. 

REDUCTION OF THE ORES. 

As the ore of tin consists simply of the one mineral, cassiterite, 
the stannic oxide, the metallurgy of this metal is comparatively sim- 
ple, the reactions involved in the reduction of these ores being theo- 
retically of the simplest character, but practically they are compli- 
cated by certain mechanical as well as chemical reactions that enter 
in. These are due to the high temperature of the reduction, which 
causes also a reduction of the oxides of other metals that are invaria- 
bly present with the tin, which are apt to alloy with it, this being 
especiallly true of the iron. Then again, the furnace in which the 
tin ore is reduced must be capable of resisting the high temperatures 
required for this reaction, and if the furnace lining is an acid one, 
consisting of silica or silicates, there is produced a certain amount 
of tin silicate ; and if a basic lining of magnesia or lime is used there 
is a certain amount of stannates formed. The silica or acid linings 
are more generally used, as most of the tin ores contain a certain 
amount of silica or silicates. Thus, while the ore is readily reduced 
to metallic tin, only a very small amount is obtained as a nearly pure 
tin. There is a great deal left in the slag and as "hard head," so that 
it is necessary to re-work the slags and also refine practically all of the 
tin obtained by the first reduction. Mr. Henry Louis* has given 
a thorough and exhaustive description of the metallurgy of tin, and 
in this paper he divides the reduction of this metal into three stages, 
as follows : 

"(a) Reduction or tin smelting proper; (b) refining the impure 
tin; (c) cleaning the slags. Each of these stages may be performed 
in more than one way, and to their various combinations the different 
local modifications of tin smelting are due. 

"Tin smelting proper is conducted either in shaft furnaces or in 
reverberatories. The former method requires as an essential condi- 
tion a supply of very pure fuel — such as wood charcoal — in sufficient 



* Mineral Industry, Vol. V, 1896, p. 533. 



54 THE TIN DEPOSITS. 

quantity and at a reasonable price, and is best suited to ores in not 
too fine a state of division and of a high degree of purity. The latter 
method requires a fuel capable of giving a hot flame and can be 
applied to less pure ores and to ore that has been very finely crushed. 
It requires, however, a good supply of refractory material and de- 
mands a higher degree of technical skill than the former process." 

Thus in the early reduction of tin ores the use of the shaft furnaces 
was the original process, and even at the present time it is still used 
very extensively in the tin districts of the far, east. In Cornwall 
the reverberatory furnaces are used and coal is the fuel, and they 
are capable of treating the finely crushed and more impure ores that 
are now being obtained. Whichever method is used, it is necessary 
to clean the slags which contain tin, both mechanically mixed and 
chemically combined in the form of silicates. The metallic tin in the 
slag can readily be separated either by fusing the slag and allowing 
the molten tin to separate out from the slag, or on account of the high 
specific gravity of the tin, it can be readily separated by crushing and 
washing the slag. 

REFINING THE CRUDE TIN. 

The tin that is first obtained has to be refined, and there are two 
different methods which are being employed at the present time, 
known as (1) "liquation" and ('2) as boiling or "tossing." Mr. 
Louis* describes these processes as follows : 

"In liquation advantage is taken of the low melting point of tin; 
impure tin is heated on the incline bed of a furnace to a temperature 
but little above the melting point of tin ; comparatively pure tin 
trickles down and is received in a large basin or 'float,' in which it 
is kept in a molten state. The residue on the bed of the furnace con- 
sists of the difficultly fusible alloy of tin and iron, known as 'hard 
head,' which generally contains sulphur, arsenic, copper, and other 
impurities. Liquation will obviously not remove readily fnsible im- 
purities, such as lead and bismuth, and the tin is purified from these 
by boiling or 'tossing.' The former operation consists in thrusting a 
billel of wood — apple-wood or cherry-wood being preferred — below 
the surface of the molten tin in (he float; steam is evolved, together 
with permanent gases produced by the destructive distillation of the 

• [bid 



THE TIN DEPOSITS. 55 

wood, and their escape throws the tin into violent agitation, projecting 
portions that splash back into the float, so that a large surface of tin 
in the molten state is exposed to the oxidizing action of the atmos- 
phere. In tossing, the same result is attained by taking out the 
molten tin by ladlefuls and pouring it back into the float from a 
height of 2 or 3 feet. By either method oxidation is promoted 
and the impurities in the tin, together with a certain quantity of 
the tin itself, are oxidized and form a pulverulent scum on the sur- 
face of the float, whence they can be skimmed off from time to time. 
The metal is allowed to stand for some hours before it is finally ladled 
out and cast into molds, so that the impure metal may settle down 
to the bottom of the float, tin being, as already stated, specifically 
lighter than most of the impurities that are apt to impair its valua- 
ble quantities." 

THE METAL TIN. 

Tin is a rather heavy metal of a pure white to slightly bluish color, 
having a specific gravity of 7.29 to 7.3 ; though the ordinary commer- 
cial tin is 7.5, being due to the impurities it contains, which are in 
most cases of metals that are heavier than the tin. It is nearly per- 
manent in the air, being affected but very little by exposure to the air, 
even in the presence of moisture at ordinary temperatures. When 
heated in the air at a rather low temperature it is gradually converted 
into the stannic oxide, which is of a 3'ellow-white color and is known 
as putty powder. When heated to a temperature of between 1,600 
to 1,800° C, if exposed to the air, it burns with a white flame. If, 
however, it is heated to this same temperature out of contact with the 
air the metal boils. The metal point of tin is variously given as from 
227° to 233° C. In this condition it forms a very mobile fluid. 
Tin is a very highly malleable metal, less ductile, its tensile strength 
being low. The usual impurities found in commercial tin are iron, 
arsenic, sulphur, antimony, bismuth, and copper, the effect of most 
of these being to diminish the ductility of the tin. They also cause 
the metal to have a didler lustre and grayer color. It alloys readily 
with many of the other metals, and considerable use is made of this 
property of tin in the arts. The readiness with which tin alloys with 
iron affects to some extent the extraction of the tin from its ores. 
Such alloys of tin and iron are obtained in the beds of the furnace 



56 THE TIN DEPOSITS. 

during the smelting operations and is known as "hard head," consist- 
ing of a dark gray, irregularly granular crystalline mass, which is 
brittle and consists of more or less metallic tin intermingled with 
definite alloys of tin and iron. 

USES OF TIN. 

The value of tin in the arts was recognized long before the begin- 
ning of the Christian Era,* and it is believed that 450 years before 
Christ, Herodotus alludes to the tin Islands of Brittany, from which 
the tin was obtained. The Phoenicians and Greeks also traded with 
Cornwall in the purchase of tin. There have been many and various 
uses devised for tin, of which the greatest is in the manufacture of 
tin plate. There has been an enormous increase during the past few 
years in the use of tin for this purpose. The tin plate manufacture 
consists of the coating or tinning of the other metals, especially iron, 
thus making what is commonly known as sheet or plate tin, used for 
roofing, tin-ware, boxes, canning, etc. This use of tin has been handed 
down from the time of the Romans, who used copper vessels coated with 
tin, though not commonly, and, as stated by Pliny, these tin articles 
could scarcely be distinguished from the silver ones, and, as far as 
we can learn, they used in their manufacture practically the same pro- 
cess that is being employed at the present time, namely, of immersing 
the copper vessel in a pot of molten tin. This metal is also used in 
the silvering of mirrors, which is accomplished by covering glass with 
an amalgam of tin and mercury. Tin foil also calls for considerable 
tin, but at the present time a great deal of the tin foil on the market 
consists of plates of lead coated with tin, which have been rolled out 
to the required thinness. Solder, which is used so extensively, is an 
alloy of tin and lend, but often containing a small percentage of 
antimony. There are a number of alloys of tin with copper, the two 
principal ones being bell metal, which contains from 65 to 80 per 
cent, copper and 20 to 35 per cent, tin, with a small fraction of a 
per cent of antimony, and bronze, which contains 93 per cent, of 
copper and 1 per cent, of tin. 

Tin oxide is also made from metallic tin, which, on account of its 
hardness, is employed as a polishing powder, and is used, especially 



•J. D. Dana, Manual of Min, and Litholoary, 8rd Edition, L880, p. 161. 



THE TIN DEPOSITS. 



57 



in the form of a paste, for sharpening fine cutting instruments. This 
oxide is also used to some extent in the preparation of enamels. The 
chlorides of tin (stannic and stannous chloride) are used in the prep- 
aration of many colors and also as mordants in dyeing. The bisul- 
phide of tin, which has a golden lustre, is used for ornamental paint- 
ing. 

VALUE OF TIN. 

There is considerable fluctuation in the value of tin, owing to the 
uncertainty of the supply and to the fact that the operators of the 
mines in the Malay Peninsula are beginning to realize their power to 
control, to some extent at least, the market, and have, therefore, been 
holding back their ore. 

The variation in the value of tin per pound is shown in the follow- 
ing table, which gives the average value for each month in 1902 
and 1903: 

MONTHLY AVERAGE PRICES OF TIN IN 
NEW YORK.* 



Month. 



January — 
February __ 

March 

April 

May 

June 

July 

August 

September . 
October — 
November - 
December . 

Year 



Price per Pound. 



1902. 



CENTS. 

23-54 
24.07 
26.32 

27. 77 
29-85 
29.36 
28.38 

28. 23 
26. 60 
26. 07 
25.68 
25.68 



26. 79 



1903. 



CENTS. 



28.33 
29-43 

3°- '5 
29.81 

29- 5 1 
28. 34 
27.68 
28. 29 
26.77 
25.92 
25-42 
27.41 



28. 09 



: Eng. and Min Jour., Jan. 7, 1904. p. 19. 



As is seen from the above table, there was an increase of about one 
and one-quarter cents per pound in the average price for the year 
1903 over that of 1902. 



58 THE TIN DEPOSITS. 

PRODUCTION OF TIN. 

PRODUCTION OK TIN FROM THE CAROLINAS. 

Tlie first production of tin ore from the Carolina belt was during 
the summer and fall of 1903, and was from the Ross mine, the ship- 
ment consisting of 38,471 pounds of tin concentrates, which were sent 
to England for treatment. There has also been a small production at 
the Jones mine during the development work, but none of this has 
as yet been shipped. 

WORLD'S PRODUCTION OF TIN. 

At the present time none of the tin used in the United States is 
produced in this country, but it is all obtained from foreign sources. 
The fact that about 43 per cent, of the world's production of 
tin is consumed in the United States emphasizes the importance of 
discovering a source of supply of this metal that can be controlled by 
this country. It is. hard to obtain accurate figures regarding the 
total production of tin in the world, for the reason that in some coun- 
tries there is little or none exported, and no reliable statistics are 
collected in these countries of their mineral production. For instance, 
in China there is at the present time practically no exportation of tin, 
altbough occasionally exports have been made of Yunan tin. The 
production of tin in China has been variously estimated, and has 
been put as high as 20,000 tons per annum; but, while these figures 
are undoubtedly too high, no closer figure can be given which would 
accurately represent the production. There is also a certain quantity 
of tin produced each year in Mexico, a very small part of which is 
exported to the United States; but as no accurate record is kept of 
the quantity obtained, the total can only be approximately repre- 
sented in the world's total production. Then again, the statistics 
regarding the Bolivian production of tin that is used in that country 
are difficult to obtain, although accurate statistics are available of 
the quantity exported. In the following table there is given an ap- 
proximate idea of I lie product ion of tin by countries during the past 

e en years, which shows the growth of the tin industry as well as 

the yearly production of each of these countries: 



THE TIN DEPOSITS. 



59 



PRODUCTION OF TIN IN THE WORLD (LONG TONS). a 



Country. 



Malay States 

Banka and Billiton 

Bolivia 

Cornwall, England 

Australia 

Miscellaneous! 

TotalJ 



1897. 



44, 9'4 

4, Soo 
5-506 

4, 453 

3.466 

360 



45,90 
14, 380 

4>464 

4,648 

2, 420 

655 



73, 499,72, 



1899. 



45, 944 

14, 123 

4,753 

4,oi3 

3,337 

970 



1900. 



47, 855 
6, 640 

6,937 

4,268 

3,178 

760 



1901. 



1902. 



1903. 



52,989 53,756 54,797 

19,365 18,76520,060 

9, 670 10, 150 9, 500 

4, 125 3,950 4, 150 

3, 276 3, 206 4, 991 

45o 350 395 



73, 14079,63889, 875^90, 177 



93, 893 



aMineral Industry 1902, p. 586; Eng. and Min. Jour.. Jan. 7, 1904, p. 18. 

t Includes production in Austria, Germany, Japan, Mexico ; and in 1903 from South Carolina. 

% This does not include the production of China. 

As is seen from the above table, there has been an increase in the 
total amount of tin produced each year, but this is still short of the 
demand for this metal, as indicated by the great decrease in the 
stocks of tin that have been kept on hand in the various countries. 
The production of the Malay Peninsula, the largest producers, has 
increased about 22 per cent, during the past 7 years ; while that of 
the Islands of Banka and Billiton, the second largest producers, has 
increased about 35 per cent. ; and Bolivia, the third largest producer, 
has increased its production about 84 per cent. England's produc- 
tion has declined slightly, and the Australian production, which is 
fifth, has increased about 44 per cent. 

The production of tin during 1903 was consumed approximately 
as follows: 43 per cent, by the United States; 28 per cent, by Great 
Britain ; 22 per cent: by other European countries ; and 7 per cent, 
by India and China. This, of course, does not include the small pro- 
ductions used in Mexico, Japan, Bolivia, etc. 

IMPORTS OF TIN INTO THE UNITED STATES. 

The tin consumed in the United States for the year ending June 
30, 1903, was obtained, according to the report of the Bureau of 
Statistics, from the countries named in the following table, which 
also gives the quantity and value obtained from each : 



60 



THE TIN DEPOSITS. 



IMPORTS OF TIN INTO THE UNITED STATES FOR 
THE YEAR ENDING JUNE 30, 1903. 



Country. 



Mala)' Peninsula — 

England 

Netherlands 

Other European Couutries 

Australia 

Japanf 

Total 



Tin in Bars, Blocks, 

Pigs, Grain or 

Granulated. 



Quantity. 
Short Tons. 




Value. 



$12,715,875 

9- 374, 563 

944, 304 

441, 114 

119.851 

23, 095 



44, 028^ $23, 618, 802 



■(•Includes a very small amount from China and Mexico. 

It will be noticed in the above table that the amount quoted as 
baving been imported from Great Britain is nearly four times that 
produced in England. This is due to the fact that a considerable 
portion of the tin produced in the Malay Peninsula is shipped to 
Great Britain from Singapore, and is in turn imported from there 
into the United States. Thus it will be seen that the greater part 
of the tin consumed in the United States is mined in the Malay 
Peninsula. That imported from the Netherlands represents tin that 
was obtained from the Islands of Banka and Billiton. Some of the 
tin imported from other European countries was obtained from Bo- 
livia. 

SOURCES OF SUPPLY OF TIN. 

The main source of supply of tin is from the Malay States, which 
furnish over one-half of tbe total amount consumed in the world. To 
increase this supply to any great extent is almost out of the question, 
at least for the present, on account of the necessity of making such 
decided changes in the method of mining, which is well-nigh impos- 
sible, as most of this mining is in the hands of the Chinese. The 
same is true of (he Islands of Banka and IJillilon, which produce 
one-fifth of all the tin used in the world. The deposits in the Chi- 
nei e Empire a re in so remote a part of the country that little is known 



THE TIN DEPOSITS. 



61 



of their extent or of their yearly production ; but it is, however, at 
the present time practically all consumed in China. The Bolivian 
mines, which now furnish about one-tenth of the world's supply of 
tin, have been constantly increasing their production during the past 
ten years, and during this time they have nearly doubled their output 
per year. On the other hand, the production from Tasmania and 
England has been decreasing. 

Although there has been an increase in the total amount of tin 
produced each year, it does not equal the demand, as shown in the 
table given below. 

In order to illustrate the increase in the demand for this metal, 
which is not supplied by the yearly production, there is given in the 
following table the accumulated stocks of tin that were on hand at 
the end of each of the past seven years : 

STOCKS OF TIN IN ENGLAND, AMERICA AND HOLLAND 
(LONG TONS).a 



Stocks on Hand December 31. 



Stock of foreign in London 

Foreign landing in London 

Malay Peninsula afloat for Lon- 
don, including wire advices. __. 
Australian afloat for London, in- 
cluding wire advices 

Banka on warrants in Holland 

Billitou in Holland 

Billiton afloat for Holland 

Malay Peninsula stock in Hol- 
land 

Malay Peninsula afloat for Holland 
Malay Peninsula afloat for Conti- 
nent 

Bolivian in Liverpool 

Total stocks 

Estimated stock in America and 
quantity floating 

Grand totals 

Trading Co.'s reserves of unsold 
Banka stock in Holland 



1S96. 1897 



18,097 

1. 174 

2, 792 

525 
1,616 
1,638 
1.742 

789 
95o 

650 
250 



3°> 223 

3,9 2 5 
34, MS 

5, 953 



15, 146 

673 

2,500 

600 
2,877 
1,328 
1, ^93 

377 
100 

600 
710 



26, 104 



4,5oo 



30, 604 



4, 333 



8, iro 
165 

1,050 



400 
,228 
,036 

>3 2 2 

454 
215 

560 

300 



15, 840 



4, 3°° 



20, 140 



3,213 



5,486 

1, 212 

2, 900 

45o 
1, 160 

470 
1,050 

100 



45o 
55o 



13, 828 



2,500 



16,328 



4,353 



1900. 



286 
297 



3,835 

35o 
837 
33o 
35o 

60 



1901. 



5, 114 
689 

2, 780 

522 
696 

329 
440 

3° 



59° 
495 



12,43° 



2, 600 



15,030 



5,347 



873 
846 



12, 319 



6,050 



18, 369 



7,251 



1902. 



4,557 
712 

2,845 

5i8 

644 

60 

333 



650 
184 



10, 503 

4,45o 
14, 953 

1, 466 



a From the annual metal circulars of William Sargant & Co., A. Strauss & Co., and Min. Industry, 
Vol. XI, 1903, p. 587. 



62 THE TIN DEPOSITS. 

As is seen from the above table, there was only one year, 1901, 
that showed any increase in the accumulated stock of tin at the end 
of the year over that of the previous year. This was an increase 
of 3,339 tons of tin in the accumulated stock, but at the end of 1902 
the stock on hand had decreased to 14,953 tons of accumulated tin, 
and at the end of 1903 it was still lower. The accumulated stocks 
of tin in the United States, which had ranged from about 3,500 to 
7,200 tons during the years 1890 to 1901 were reduced during 1902 
to less than 1,500 tons. 

These figures illustrate emphatically the need of new sources of 
Supply of tin, and why new deposits like those in the Carolinas and 
Alaska should be thoroughly investigated. 

One result of this scarcity in the supply of tin and consequently 
the high valuation of this metal has been the utilization of old tin 
cans and other scrap tin as a source of the metal. The amount of 
tin that is recovered each year in this way, while not large, is steadily 
increasing, and it is becoming an industry of some considerable im- 
portance. There are now a number of companies that have been 
organized for this purpose, of which the more important ones are the 
Vulcan Detinning Company, whose plants are at Sewaren, 1ST. J., 
and Streator, 111. ; the Ammonia Company of Philadelphia, and the 
Johnson & Jennings Company of Cleveland and Chicago. In recov- 
ering the tin from the scrap, this latter is digested in an alkaline 
solution and the tin eleetrolytically precipitated therefrom in the 
form of a powder, which averages 80 per cent, metal.* The sheet iron 
that remains, which contains a little tin, is melted and cast into win- 
dow-sash weights and other objects where the small percentage of 
tin in the iron is a desirable feature. 



•Min. Ind., 1902, p. 585. 



PUBLICATIONS OF THE NORTH CAROLINA GEOLOGICAL SURVEY. 



BULLETINS. 



1. Iron Ores of North Carolina, by Henry B. C. Nitze, 1S93. 8°, 239 pp., 20 pi., 
and map. Postage 10 cents. 

2. Building Stone in North Carolina, by Joseph A. Holmes, George P. Merrill 
and T. L. Waison. 7S>»«jmU>' iiiMiir. 

3. Gold Deposits in North Carolina, by Henry B. C. Nitze and George B. Hanna, 

1896. 8°, 196 pp., 14 pi., and map. Out of print. 

4. Road Material and Road Construction in North Carolina, by J. A. Holmes 
and William Cain, 1893. 8°, 88 pp. Out of print. 

5. The Forests, Forest Lands and Forest Products of Eastern North Carolina, 
oy W. W. Ashe, 1894, 8°, 128 pp., 5 pi. Out of print. 

6. The Timber Trees of North Carolina, by Gifford Pinchot and W. W. Ashe, 

1897. 8°, 227 pp., 22 pi. Postage 10 cents. 

7. Forest Fires: Their Destructive Work, Causes and Prevention, by W. W. 
Ashe, 1895, 8°, 66 pp., 1 pi. Out of print. 

8. Water-powers in North Carolina, by George F. Swain, Joseph H. Holmes and 
E. W. Myers, 1899. 8°, 362 pp., 16 pi. Postage 16 cents. 

9. Monazite and Monazite Deposits in North Carolina, by Henry B. C. Nitze, 
1895. 8°, 47 pp., 5 pi. Postage If cents. 

10. Gold Mining in North Carolina and other Appalachian States, by Henry 
B. C. Nitze and A. J. Wilkins, 1897. 8°, 164 pp., 10 pi. Postage 10 cents. 

11. Corundum and the Basic Magnesian Rocks of Western North Carolina, by 
J. Volney Lewis, 1895. 8°, 107 pp., 6 pi. Postage J/ cents. 

12. Drinking Water Supplies in North Carolina, by Joseph A. Holmes. In 
preparation. 

13. Clay Deposits and Clay Industries in North Carolina, by Heinrich Reis, 
1897. 8°, 157 pp., 12 pi. Postage 10 cents. 

14. Mica Deposits and Mica Mining in North Carolina, by Joseph A. Holmes. 
In preparation. 

15. Mineral Waters of North Carolina, by F. P. Venable. In press. 

16. A List of Elevations in North Carolina, by J. A. Holmes and E. W. Myers. 
In preparation. 

17. Historical Sketch of North Carolina Scientific and Economic Surveys; and 
Bibliography of North Carolina Geology, Mineralogy and Natural History, by 
J. A. Holmes and L. C. Glenn. In preparation. 

18. Road Materials and Construction, by Joseph A. Holmes and William Cain. 
In preparation. 



64 PUBLICATIONS OP THE SURVEY. 

19. The Tin Deposits of the Carolinas, by Joseph Hyde Pratt and Douglass B. 
Sterrett, 1905, 8°, C4 pp., 8 figs. Postage 4 cents. 

20. The Loblolly Pine in Eastern North Carolina, by W. W. Ashe. In prep- 
aration. 

ECONOMIC PAPERS. 

1. The Maple Sugar Industry in Western North Carolina, by W. W. Ashe, 1897. 
8°, 34 pp. Postage 2 cents. 

2. Recent Road Legislation in North Carolina, by J. A. Holmes. Out of print. 

3. Talc and Pyrophyllite Deposits in North Carolina, by Joseph Hyde Pratt, 

1900. 8°, 29 pp., 2 maps. Postage 2 cents. 

4. The Mining Industry in North Carolina During 1900, by Joseph Hyde Pratt, 

1901. 8°, 36 pp., and map. Postage 2 cents. 

5. Road Laws of North Carolina, by J. A. Holmes. Out of print. 

6. The Mining Industry in North Carolina During 1901, by Joseph Hyde Pratt, 

1902. 8°, 102 pp. Postage J t cents. 

7. Mining Industry in North Carolina During 1902, by Joseph Hyde Pratt, 

1903. 8°, 27 pp. Postage 2 cents. 



REPORTS ON RESOURCES. 

Vol. 1. Corundum and the Basic Magnesian Rocks in Western North Carolina, 
by Joseph Hyde Pratt and J. Volney Lewis. In press. 

Vol. 2. Fish and Fisheries in North Carolina, by H. M. Smith. Nearly ready. 

Vol. 3. Building Stones of North Carolina, by G. P. Merrill, F. B. Laney and 
T. L. Watson. Nearly ready. 

Vol. 4. Miscellaneous Mineral Resources in North Carolina, by Joseph Hyde 
Pratt. In preparation. 



These publications are mailed to libraries and to individuals who may desire 
information on any of the special subjects named, free of charge, except that in 
each case applicants for the reports should forward the amount of postage needed, 
:is indicated above, for mailing the bulletins desired, to the State Geologist, Chapel 
Hill, N. C. 



to th C ■ State Librae 

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